Yes compression can even out the dynamics of parts of your mix. You want to learn to identify what compression sounds like, however.
Put a compressor on one of your individual parts. Raise the ratio to at least 4:1 if not more, and then start adjusting the threshold control. Listen very carefully as the threshold is lowered, and the compressor starts to act upon the audio you are feeding it. Things will start to seem quiter, generally, as the amount of compression is increased.
Attack time adjusts how fast the compressor reacts to the start of a signal. Release time adjusts how long it takes the compressor to let go, after the input signal stops. Adjust both of these and again, listen to how things change.
Usually, you don't want the compression itself to be noticeable. that is, you don't want to be listening and think to yourself "wow, I can really hear the compressor clamping down on that signal". Unless you are after a special effect, compression, like EQ and every other tool we have, is best used in moderation! A little goes a long way.
Generally, with things set aggressively, lower the threshold until you are definitely getting some compression on your material, then, once you have attack and release set to taste, back the ratio off.
Hope that helps some. just about any book on mixing will have a chapter or several chapters on compression.