Found this on page 3, trying to catch up after my vacation. I think you are doing a great job mixing for a newbee in mixing. I listened to both pieces and they sound pretty good. I would add this, never let your tracks share the same space in a piece. Make each track as concise and clear and clean sounding as possible, so when you start the mastering process you can find your problems on each track and the use what you need to fix each track, but don't over due it. When each track has been done solo, then see how they all sound together so you can find what is missing. I may need some reverb, equalization, panning of the track, stereo imaging, limiting, excitement, post equalization, maximization setting on drums, instrumentation or vocals. Vocals should always stand out front. Listen to Robbies vocals, they are up front always. Your doing a good job and reading and practicing over and over again and learning your software all comes to fruitation with time. Do very good from what I have heard so far. Keep at it.
Peace and Blessings, John