When mixing stereo you have two tracks. Left and right. Make use of this. You can drastically clean up your mix by panning sounds nicely. Be brave try extreme things and come back gradually to more normal settings to find new ways. To make your sound more broad you can do a couple of tricks. For example:
- Try Stereo enhancer plugins (www.betabugsaudio.com has one for free) But don't only try it on tracks but also put it on the inserts of your effect channels and broaden your reverbs or other efx.
- Chorus with slow rates can also broaden your sounds.
- Copy a track. Pan one full to the right the other full to the left and then delay one for 10ms and pull the other for 10ms, this will give you a very broad sound too.
- "Doubler" plugins will virtually double your track and actually do the same.
- If you play a guitar track, play it twice, record it twice, put one record left and one right. Or if you are using synths you do different filter movements for the left and the right side by exporting it twice and than panning it.
But keep in mind: Don't just make everything broad, you need the contrast!