Mix/master critique

I am trying to learn how to mix and master, following the many guides in this forum, and a few books and additional resources.  I've just mixed and mastered 3 songs, and would like honest critiques.  Not on the songs themselves, lyrics, compositions, etc.  But strictly on how did I do as a mix engineer?  All that said, I don't know if this is the proper forum to post this in.  I didn't post in "Songs" because I am not looking for attaboys on the songs.  Just honest critiques on the mix.  Are all parts balanced?  Did I achieve enough separation, etc.
 
If you have a couple minutes, and are able to provide feedback and critique, I thank you for your help.  I know a lot of you are pretty good at this, and many are pros.  I'm still learning...  
 
I have uploaded the songs to Dropbox.  Below are the names, followed by the long URL, followed by the short URL.  They are in the order on which I would like critique.  If you can get to all three, great, but if only one, then please critique "Forgotten Land".
 
Thank you very much!
 
Forgotten Land
https://dl.dropboxusercontent.com/u/14864402/Forgotten%20Land%2C%20mastered%2C%2044-16-P3%2C%208-29-14%2C%20(c)%202014%20Todd%20Silva.wav
https://db.tt/TfH49Y1U
 
Red Skye
https://dl.dropboxusercontent.com/u/14864402/Red%20Skye%2C%20mastered%2C%2044-16-P3%2C%208-29-14%2C%20(c)%202014%20Todd%20Silva.wav
https://db.tt/SFH7C9vf
 
Prairie
https://dl.dropboxusercontent.com/u/14864402/Prairie%2C%20mastered%2C%2044-16-P3%2C%208-29-14%2C%20(c)%202014%20Todd%20Silva.wav
https://db.tt/ppeJKBWV
 

Thanks CPFC1985. I'll do that.