If you play Terran, remember two things;
If you aren't attacking, you're expanding,
If you're attacking, keep up the pressure and see to the end of it.
- Marine rush (two barracks, each with one of the two building upgrades + Armoury (research armor over weapon first, always and then alternate))
- Vulture rush, spider mines, self explanatory
- Barrack rush, send an SCV to an enemy expansion/base early in the game, set the barracks down and spam some good ole' terrans
- Reaper rush, these guys are a huge pain in the ass early in the game if you use them correctly, they jump over buildings and sting like a bitch, use them to eliminate and harass opponents peons, they're super effective
Zealot rush, slow but deadly and their damage/shield count is ridiculous.
Void ray, these units are super annoying and i cannot tell you how effective they are at just, blowing shit up.
Zergs, remember one thing here;
It's all about momentum and impetus when you're playing zerg, their units are relatively weak in comparison to the two other races but they produce quickly and you shall use that to your advantage.
Zergling rush, self explanatory
Ultralisk/Hydralisk + Zergling build if you want to be an asshole
Hope that helps \m/