-when starting out with your resource gatherers, try and choose minerals that are closest to your main building. This will allow you to gain a few more minerals every minute or so, this can be important early on.

-attack move is really important. Your units will attack enemies while they move to the area designated. [select unit press a and click at a spot].

-use your scv's, probes, or drones to attack if your being rushed and losing... They may save you

Protoss Strategies(these are just suggestions, they usually work for me, and I try to stay away from the obvious strategies)

-to gaurd against zergling rush, build a pylon leaving about 2 spaces in between the nexus and the pylon, then build a forge next to the pylon and again if possible leave 2 spaces inbetween, and when the forge warps in, try and fit in a few cannons inbetween the forge/pylon and nexus. So you should have a row made of the forge and pylon and another row of cannons. The buildings provide good cover against most units because they usually have to go around them and not as many units can fit in and get their attacks in.

-a large group of up graded coursier's are able to take out large huddled groups of overlords quickly, and the can take a number of hits before being destroyed, and also they can run past defenses quickly with little loss.

-if playing against a terran, building cannons just out of site near their base can destroy them easily(in the beginning). Marines generally get mowed down by cannons and the enemy can pretty much only take out the cannons with seige tanks which they will not have if you do this early. But you sacrifice a lot of money and buildings that could have been built at your base if you fail.

Terran Strategies:

-SCV's are the strongest of the resource gathering units. 60 health and able to be repaired by other SCV's... Sometimes sending in 2 SCV's into an enemy base right in the beginning can slow him/her down a lot. Just attack a building and if all their drones attack, just run off a bit and come back or if he sends 1 or 2 drones to take out yours use one to attack and the other to repair. Another interesting thing to do if you play another terran is to use a few scouting SCV's to attack their SCV's while they are building a barracks or supply depo. building will be halted if the SCV is destroyed and it cannot attack back while building.

Zerg Strategies:

-if playing another zerg, you can build creep colonies at the base. Doing this early can have many positive effects, even if it doesnt succeed in destroying the enemy. First just find the enemy base and try and hide the colony some where and if the enemy finds it and sends his drones just cancel the colony and run, and then come back if he stops chasing. Hopefully you can morph it into a sunken colony before he can. If all their drones are used to try and take down the sunken and succeed, this still has a possitive effect because you should take out at least one drone and you stall all his drones from doing other things.

-playing non zerg opponents you can often keep enemy buildings away with your creep. Building creep colonies close to enemy bases can prohibit them from building defense on the outskirts of their bases.

-Excess overlords can often provide excellent coverfire, just fly them in just slightly before your units go in to attack and the over lords will take a lot of damage that your other units would have likely absorbed.