Protoss double gateway build>>
This build can be characterized by the starting build order of pylon, gateway, gateway, pylon (or something to that effect). This is a moderate tech build which means the player will usually gain tech at a steady pace and is capable of easily branching off to any side of the tech tree. If they get tech faster, that means that they have neglected an early zealot defense meaning you could probably kill them early on so remember to scout. Usually, with this build they will stick to ground units, especially dragoons, and during team games, if two or more protoss players are on the same team, 90% of the time they will all go mass zealots to control the early-game, which is bad. If this happens you have to gain tech fast and still have a good defense, but that is usually easy if it is a team game.
protoss counter-
in this situation, use the double gateway build also. The two deciding factors of the game will be 1: your use (or his) of the appropriate unit counters so it is best if you find his strategy out and hide your from him and 2:Who is the trickiest and who will go all out.
zerg counter-
when playing as zerg, it is a good idea to get tech fast, possibly lurkers and to expand a lot. Drops work well if they are done early-on. Also, be very aggresive so that your enemy is forced to constantly replenish his defense, thus slowing him down greatly. So by the time he thinks he has stopped your last attack, you will have guardians at the rear of his base, hydras and lurkers at the other end of his base, and zerglings piling in through the entrance.
terran counter-
Get to tanks fast but do not neglect your troop build-up. The idea is to pressure your enemy early-on with infantry and to have tanks by the time he thinks he has stopped your attacks. A good strategy would be to tank push to his base, and barriade him or control the center of the map, allowing you to expand.
Tech Rush>>
One can recognize this build by the early procurement of gas, singular types of buildings (one gateway, one cy-core, one forge, etc...), very weak early defense, and lack of upgrading. Sometimes they will begin by cannoning their entrance, which is a good sign that they are teching up fast (which means if you have siege tanks, use them). It usually very easy to tell if someone is using this strategy. With protoss, they are most likely DT rushing. If you see two cy-cores go up then they are going air, most likely carriers, which means you must take the appropriate counter measure. The basic counter idea is simple: He is rushing tech, leaving him with few units in the beginning; therefore, you must build so that you will have many units in the beginning that will crush him.
protoss counter-
With protoss, it is best if you build up as usual (maybe with an added early cannon or two for detection against DTs) so that you will have a more powerful force than your enemy. Attack early when he is weak. If he makes it past the weak stage, you can just get the right counter unit of his strategy because usually when tech jumping, people stick to the one unit they were trying to rush to. Also, he will not have a good perimeter defense; hence; he can be subject to drops.
zerg counter-
As with protoss, it is best with zerg to kill your enemy early. If you cannot then you should expand and dominate the map, and if you can, do not let your enemy expand. Also, try to get to lurkers and drop them a.s.a.p as this will most likely screw up his strategy.
terran counter-
get detection fast as there will most likely be DTs. Go mass infantry to overwhelm is weak defense. If you make it to middle or late game then just play normally (aggressively).
turtle build>>
This is a build most commonly used by newbies who want to feel secure. Be happy when facing one of these as it is the easiest to defeat. You can tell if someone is using this by an early cannoning of his entrance, a wall defense around his base, little or no map activity on his part (he stays insde his base), rows and rows of gateways/stargates/robo-facilities/etc.. but no troops. The thought in this strategy is, "Stay in my base, build up, and send everything I have crashing out of my base, hoping that he does not have anything better." counter-
Since the basic idea for all races' counters are the same in this case, the general counter will be described. When facing a turtling protoss, it is best if you take advantage of his lack of expanding and dominate the entire map. Also, do not let him expand. It will be so funny when he has all those gateways but can only make seven dragoons because his minerals cannot support more. Once you have your position set up, (i.e. you are secure in your map development e.g. chess, Independence Day) you should put your main strategy into action if you have not already (you should have come up with a strategy while you were positioning yourself around the map). Now if you are not that creative, here are some working concepts:

· Siege his ass-use tanks, guardians, reavers, etc... to unpeel his shell, forcing him to blindly send whatever he has to try to stop your units (which you will have a surplus of).

· Drop him early-most likely, he will not have side and rear defense for some time, so kill him early.
Never-ending attack-the name speaks for itself. Just pummel your enemy over and over and over and over again and again. Eventually he will break. Just make sure you will have plenty of defense just in case he stops your attacks and decides to attack you.