Several good ways of doing this. If you know a bit about construction, you can approximate pretty easily...but I won't go into that.

There are all sorts of gadgets to make this easy. The ones that come to mind fastest are the magnetized ones or the ones with the little leds on them. Basically they sense the nails in the studs and then use that to tell you where your stud is. I think every hardware store sells one now. I don't have any experience with these though.

Another method, which you brought up, is the tap and listen method. This works pretty good, though you do have to know what you are listening for. To find out, do this. Tap around 8" below the center of a window. Provided you don't hit a stud, you should hear a slightly hollow sound. Then tap directly under the side of the window about the same distance down. You should hear a more thuddy sound.

This can then be followed up with the tried and true pin method. Stick a pin in the sheet rock, if you can't push it past the sheetrock then you hit wood.

Any of these methods should be followed up by a drill hole using a fine drill (easier to patch the mistakes) that will tell you for sure if you are hitting wood. Look for wood bits.

Once you find one stud, then all the rest should be on 16" centers. There are more around windows or other wall features, also there is blocking between studs that can make for a confusing time trying to find a stud per earthquake and fire codes.

The trick is that the blocking is horizontal...the stud is vertical...:)