I want to get a thread out here for base locations, mainly because the one at the trem forums is for 1.1, and it can be misleading (Some of the bases they give suck really badly in gpp). I'll start us out with human bases and fwd bases in atcs. (I'm going to have to break this up since it contains many images)
Main Bases
First, plop a turret near the RC
Then one on the ledge
While those are building, mark the two turrets on the bottom entrance, and the arm and medi. I'm going to stick the turret setups here, so that they may be used in the descriptions of main bases, however, do not build more than 1 ret outside the main base, until teh main base is complete.
These are (IMO) the most common setups. I prefer the first, because of the easy access to the medi, however, humans standing there can interrupt the kill zone (The area where the ranges of the rets overlap).
This one is nice because of the larger and less obstructed kill zone. A 3-ret setup would be good here, so that another ret could be stuck closer to the RC.
Again, larger kill zone. A 4-ret setup may be used.
This has the largest kill zone; however, it requires movement of everything in the base, so it takes longer to set up. Both a 3 or 4 ret setup may be used, in a 3-ret, another ret goes by the RC.
Forward Bases
This is a nice base if you have a couple extra bp.
This is also a good complement to the first fwd base, if everything is going well.