TimS gave good advise about "fast and splashy", perhaps I would add that you have to crank VERY, VERY fast.
I have never caught one with a fly rod and doing so from shore would be a great feat. I was in Costa Rica a few months back for business purposes and in the only day that I wetted a line the water was terribly muddy because of torrential rains and I was not able to even see a roosterfish. They don't like turbid water because they are 'chasers' not 'ambushers' and feed using a lot their eyes. I am sure I will catch a roosterfish with a lure Tim sold me in the first opportunity I have because it has good action for them (a Lex Lures Pencil Popper 3), but one lure that you absolutely cannot go wrong with is Robert's Ranger in 3 oz. They are made in Martha's Vineyard.

What you should do to fish for roosterfish in CR is:

1.Choose your weapon correctly. You need a far casting combination that will permit you to cast almost non stop +100 yds away for several hours and with little risk of a break or weakening the line because of backlash (conventional) or twisted line (spinning reels). Roosterfish are tremendously strong fighters, but most of the time stay away from rocks. Using +30 lb lines permits you to fight better but I use a 125 - 150 yd of 15 to 20 lb mono topshot and braid of slightly higher breaking strength as backing. This to cast further and increase the hookup rates. You can not go wrong with a 3 oz Ranger in white/red color, if you don't raise roosterfish on this lure you have little chance of raising it with any other one, so stick with it until you have hooked several and feel like experimenting. Use of a 50 lb bite leader, a ball bearing swivel and an appropriate length 30 lb shock leader for power casting the 3 oz lure is a sine qua non condition. (**I'm guessing "sine qua non condition" is sort of like a no brainer?  TimS)

2. Operate your weapons correctly! Don't use conventionals on roosterfish unless you can crank at blender speed for long periods and cast them far in a very controlled way (most retrieve less inches per crank than similar capacity spinning reels). A good and not too expensive roosterfish combo would be a Daiwa Emblem EM-X5500A spinning reel mounted on a Daiwa Sealine-X 12' spinning rod (Check the spine of the rod carefully before you buy it!). 
The MAIN trick when fishing for roosterfish is to use a skipping lure cranking so that the lure skips constantly on the water and it is most of the time entirely or with most of its body out of it. This is easier to attain with the X5500A, because it has a very high retrieve ratio and an exceptionally wide spool. When you see that roosterfish erupt from the water and starts wildly attacking the lure, DO NOT SLOW DOWN BUT CRANK FASTER!. If you slow a very small fraction down, the roosterfish will shy away instantly, I can almost guarantee that. If the roosterfish seems like it is going to run out of water and beach himself, DON'T STOP, but bring the lure out of the water and in one swift motion cast again out and start retrieving fast again. The roosterfish will practically always grab the lure from behind and you should KEEP CRANKING fast even if you see that the lure is in his mouth, KEEP CRANKING and set the hook only after line starts peeling off your reel like if you hooked a car passing by a highway.  I am going to make a plug here regarding the use of an item called "The Cannon" by Breakaway. Power casting with spinning reels is practically impossible without tightening the drag very hard or locking the spool with some sort of devise. You can even hurt your finger badly if using a heavier lure or lead and a soft drag as the line will slip no matter how hard you hold it against the rod. With the Cannon, you can set the drag accordingly with the line test (rather low on most cases) and lock the line safely for the cast. If you want to use it, e-mail me for a diagram showing a trick for better gripping.

3. Choose a good hunting ground. Ask reliable sources where roosterfish have been feeding recently. When you get to roosterfish territory, don't take your eyes off the water and look for roosterfish charging baitfish. A 30 lb roosterfish can be seen feeding a mile away under good conditions. They will probably be feeding on mullet. I don't have to explain what does a roosterfish feeding looks like... you will instantly see what I mean. Instead of me telling you what type of place you should be looking for, you will be more successful if a reliable source tells you where they have been feeding recently. Be patient, hunting roosterfish is like hunting big game on land in many ways. 4. Please release ALL roosterfish ASAP! A mid size roosterfish will take at least half an hour to land and it will probably be very exhausted if using 15 - 20 lb line. They don't give up easily and literally fight to death. Bring some pliers and tell your partner to have the camera ready so you can put him in the water fast or he will die. Don't just let him stay there floating upside down, but hold him straight and revive him much like you would any other fish. Sometimes this operation can last 5 to 15 minutes, specially when the fight lasts more than an hour, so please be patient.  Hope this helps! Sergio

Here's a roosterfish I caught recently! (**Editor's note: Please note smile on anglers face...these things must be a blast to catch! ;)

PS That was a long post ! (Please don't ask about snook from the surf as the post would be much longer ;-)

Thanks Sergio...I'm going to ask you about catching snook from the surf...just to keep ya busy! ;-)

         TimS