Mixcraft Memory issues? Never had that one (ok, I guess I have, CPU load issues - use the Freeze Track command Ctrl+F)... Hmm.
About "not improving", just work at it. Believe it or not, an absolute great way to organize Mixcraft is to change the track names to whatever they are used for. Say, if I have several instances of the same VSTi open, it does well for me to rename the track to something completely different. Try naming the tracks to something that describes the sound of that track.
Also, work with the Automation lane. It's a great thing to use.