What settings are you using on the limiter? The limiter is definitely your key to getting your track louder on the master channel. Make sure the ceiling is set to below -0.01, this way the level will not hit the ceiling and clip. Start increasing the gain until your mixes compares to a commercial release (maybe open up a track you want to compare in quicktime and reference it with your track. I would say a 4-6dB increase will increase the volume enough. But it depends on your mixes.
Also on the Master Track drop your level a bit to give your track some headroom. Maybe drop it by about 2-3dB
This is just some basic advice. Your best bet is to take a look at our mastering tutorials. To get the best out of your mastering you'll export your mix out and bring it into a new Ableton project. From there you will apply the mastering processes (multiband dynamics, stereo wideners, limiters etc...). Working with a stereo file as opposed to a mix with multiple tracks will give you a more critical view of the mix. And mastering processors applied in a mix with multiple tracks can sometimes have a negative effect.
For more mastering advice check out the following tutorials:
[url]http://www.macprovideo.com/tutorial/protools10401[/url]
[url]http://www.macprovideo.com/tutorial/from-demo-to-master[/url]
These tutorials aren't Ableton specific, but you can apply the same techniques in Ableton using the built-in effects or 3rd party plugins.
Hope this helps. Mastering is a skill to its own, and can take some time to get your tracks comparable with commercial tracks. But keep up the hard work, you'll get there!
