There are so many tips and things online for this game.. it's really amazing.
There are also lots of videos on YOUTUBE to help you out as well.
Here are some examples of great videos to check out.
For those of you who are stuck in Bronze League because you lost your placement matches.. there is still hope.
Try playing Protoss and doing the Zealot Proxy rush. I have won countless matches in Bronze league doing this, and I got out in one night. It's really easy against players in Bronze, but kind of harder to pull off once you reach Silver league. So make sure you can hold your own in Silver if you reach it this way.
For those of you who don't know what I'm talking about:
Start off by sending one of your probes to scout at the beginning.
Keep making probes until you're capped at 10/10. (save your Chrono Boost)
Find a nice spot near your opponents base where he won't find you if he chooses to scout or push you.
Build a pylon, then 2 Gateways.
Put as many Zealots on queue as you can, and continually use Chrono Boost to get 4 out, then push.
8 times out of 10 you will succeed and they will give up.
Congrats you have just accomplished your first CHEESE!