There are EQ, reverb, and delay of course, but the two most important things that affect this are:
1. Sound selection. Some sounds (because of their frequency content, transients, etc.) sound "up front" and some naturally sound more background-ish. (Example: try making a shaker take the "up front" position. It's hard to do since it's a high-frequency sound and it wants to be in the background.)
2. Volume.
I know this sounds simple, but if you can't get a sound *almost* where you want it with just these two, adding tons of processing isn't going to help.