Before you even reach the first tee, there are a few things you can do to help lower your score.
Window layout - instead of having just the full main view displayed, try dividing up the screen so that you can see more information about the layout of the course and your current ball location. A good setup is Main Normal on the left, Green Small on the top right, and Profile on the bottom right. The Green Small view lets you see what kind of approach to the green you'll have (good for telling where doglegs are), and where obstacles like trees or sand traps are near the green. The Profile view shows how far above or below the hole your ball is, which can affect the distance you need to hit your shot. Don't always trust the caddy's club selection, its based only on the distance to the hole, not the elevation. The Top view can also be a useful window option, as it shows the general layout of the hole and gives a rough idea of where trees & other obstacles are.
Choosing your clubs - make sure you have a good feel for the distances you hit each of the clubs you are carrying. It doesn't matter which clubs you carry, but knowing how far each goes can help you better select the right club for a shot. Some clubs go roughly the same distances, like a 4 wood and 1 iron, so you don't need to carry both. Also important is the chipping club you select, the default 8 iron is a bit harder to control than a Pitching Wedge, and you may find better results if you switch.
On the Tee:
Setting up your driver - for maximum distance off the tee, you should change the stance setup for your Driver. Moving the ball up in your stance (towards the top of the Setup window) will give you more loft (and more distance), and make hooks & slices less severe.
Hitting for distance & accuracy - the farther past 12 O' clock you hit your power snap, the farther the ball will go, but the harder it is to hit accurately. Try hitting around 110% (a few pixels past 12 O' clock), which will give you a bit of extra power without being completely wild.
Aiming & avoiding obstacles - always click and drag the aiming stick in the main view to the spot you want to hit your shot at. Aim as far down the fairway as you can, since the closer to your target you aim the more accurate the angle between the ball & aiming stick is set. Also, using the aiming stick you can tell what kind of landing area you will have on your shot. If there is rough or water 300 yards out (for instance the hole is a dogleg), you may want to hit a shorter shot, or hook/slice the ball around the dogleg.
On the Fairway:
Approach shots - when you are close enough to land your next shot on the green, accurate aiming and power are very important. Check the elevation between the ball and the hole(with the aiming stick), so you can hit with the right amount of power. If you are below the hole, use more power or choose a longer club. If you are above the hole, club down or hit with less power. Generally for every 20 feet of elevation change you need to adjust the distance you are hitting by 10 yards (i.e.. 20 feet up hill plays 10 yards farther). Its better to hit too long than too short, in case you don't hit the accuracy mark perfectly. On short approach shots in Links, the ball may drift a bit to the right, so you may want to aim a few pixels left of the hole.
Laying up - sometimes you may not be able to reach the green from your fairway shot. In this case, try hitting a short shot down the fairway that will leave you an easy chip or short wedge to the green.
Off the Fairway:
Normal rough - When your ball is in the rough, you'll need to hit the ball harder to get the normal distance for each club. Your caddy will usually select a club a bit shorter than you need, so sometimes you should to hit a little more than 100%.
Heavy rough - this takes even more distance off your shot, and also penalizes more you if you mishit the accuracy mark. Try to club down as much as needed to hit your shot below the 100% power mark, so you don't have to overhit it.
Behind trees/obstacles - there are two shots you can use to get to your target when a normal shot would be blocked - over or through. Hitting a high shot over the trees is the best shot, since you don't have to take the chance of getting a bad ricochet. The shorter club you use (wedges are best), the higher loft you will get on the ball, and the better chance you have of clearing an obstacle. For added loft, temporarily change the Setup for the club by moving the ball forward in your stance. Its better to use a shorter club with over 100% power than a more controlled longer club, since you'll get more loft. If you are too far away from the hole to use a short iron, you'll have to punch your shot through the trees. Move the ball back in your stance and club down, hitting less than 100% to still get the right distance.
Cart paths/concrete - if you your ball comes to rest on a cart path or road that isn't out of bounds, you can drop without being penalized a stroke. Its best to rotate the view 90 degrees left or right and drop to the side, since you can't drop closer to the hole but should try to drop on fairway or light rough.
Fairway bunkers - Hitting from a sand trap a long distance from the green is much like hitting from heavy rough. Try to hit as close to the accuracy point (6 O'clock on the swing meter) as possible, since any slight variation will be magnified on a long bunker shot.
In a hazard - in the unlikely event you hit into a hazard, the spot you drop out of the hazard is very important. Try to drop on fairway or light rough, far enough away from trees that you have a clear shot to the green. Its better to have a longer open shot than to drop closer to the green but behind an obstacle.
Around the Green:
Chipping - the short game is one of the most important part of your Links play. You'll gain or lose more strokes here than in almost any other part of the game. Links defaults you to an 8 iron for chipping, but it is easier to use a Pitching Wedge, since it goes shorter and allows you more control. When chipping, your maximum power is reduced by half, and you can't hit with more than 100% power. The part of the swing meter that is disabled is drawn in green. The most important part of chipping is hitting the accuracy point on the downswing. The difference between hitting it perfectly and one pixel off can change the distance you hit by 10% or more. For instance, the PW hits 34 yards from the fairway with a perfect shot (100% and exactly at 6 O'clock), but if you hit 100% but miss a pixel at the bottom it will only go 30 yards. Another key to chipping is reading the distance to the hole correctly. Sometimes it is listed in feet, sometimes in yards (farther than 60 feet becomes yards). For chips longer than 30-34 yards, go to a 9 iron or 8 iron, which will let you hit up to 40-45 and 45-50 yards respectively. When chipping out of the rough or heavy rough, you should hit 20% to 40% longer. If you are on the fringe (on fairway around the green), you can use the old "Texas wedge", or putter, to putt the ball instead of chipping, which will usually give you a more accurate shot. Putt a bit harder to get the ball onto the green, and take the green's break into account like a normal putt.
Sand shots - hitting from a sand trap near the green is much like hitting out of heavy rough. If the distance is short enough, chip the ball hitting it a bit harder than you would out of heavy rough. Again accuracy is the key, if you miss-hit at the bottom of the swing, you'll lose distance. If the bunker is very deep, forming a lip between you and the hole, a chip shot may not clear the edge. Try switching to a normal(non-chipping) L wedge or sand wedge, and move the ball up in your stance for extra loft. In the worst case, you may have to rotate the view and chip sideways to get out of the trap.
Under a tree - if you are within chipping distance but under or behind a tree, the chip shot may hit branches and not reach the green. In this case you can try hitting a long iron normally(not chipping), to punch the ball under the tree and onto the green. Select a long iron (2 or 3), and hit as short as you can (let go of the mouse immediately on the upswing). The shot should stay low and go about 40-45 yards from the fairway, less from rough or heavy rough.
On the Green:
If good chipping helps you save strokes, good putting helps you win tournaments. Bad approach shots or chip shots can be saved with a good putt, and good rounds can be ruined by a few 3+ putt greens.
Reading the break - use the grid to see the break of the green. Look at just the grid lines between the ball and hole, and see whether the lines are straight or go down to the right or left. A small break (the grid lines only drop a pixel or two across a grid square) will require you to aim a couple of pixels above the hole. More break (steeper grid lines, going 4 or more pixels down across the grid), will require you to aim farther above the hole. The amount of break accumulates with each grid line the ball passes over on its way to the hole, so even a minor 1 or 2 pixel break will add up on a 40 foot putt (if it breaks all the way). You can negate some of the break by hooking or slicing your putt slightly up into the break.
Gauging distance - hitting the ball the right distance is key to making long putts. Each dot on the swing meter is equivalent to about 10 feet. On short putts, you always want to hit a bit harder than normal. Anything between 5 and 9 feet you should hit near the first dot, and anything under 5 feet you should hit around halfway to the first dot. Before you hit your putt, make sure and use the aiming stick to see how far above or below the hole your ball is. If you are putting uphill, you'll need to hit a harder shot to get there. Putts won't break as much going uphill, but will break more than normal if you hitting downhill.
In the Clubhouse:
Scorecard/stats - after a round take a good look at your scorecard and end of game stats. The scorecard will tell you which holes you have trouble with, and should try practicing some more. The end of game stats have a wealth of information about your round, including:
Drives in fairway - if this isn't above 70%, you should try hitting with less power off the tee so you can shoot more accurately. An extra 30 yards on your drive doesn't help if you are in the rough or behind a tree.
Greens in regulation - this tells how many holes you were on the green putting for a chance at birdie. You should try to get at least 75% here, if it is lower you need to practice your approach shots. Hitting a bit longer drive off the tee may also give you an easier second shot to the green.
Total putts - as the saying goes, "drive for show, putt for dough." You can take the most strokes off your round by putting well. Try to get in the low to mid 20's, keeping it below 28. If you have trouble putting, go into practice mode and try putting on several greens until you can make shots consistently. Take mulligans until you can hit a shot well, then move on to the next hole.