I personally would love to see a tutorial on prepping your mixes for mastering. Not so much mastering, but how to get your mixes prepped to be sent out to a professional mastering studio - including this newfangled thing I've heard a lot about lately - stems.
1) Make your mix sound awesome, do not leave something sounding unfinished so that "it can be fixed in the mastering", which is totally untrue to the boot. Fix all errors in the earliest stage possible
2) Leave a lot of headroom and keep the RMS quite dynamic, for example peaks at -3dbFS and RMS -18dbFS. Do NOT brickwall limit your mixes yourself, because the mastering guy most propably has better brickwall limiters than you
3) Ask your mastering house/engineer in what format they want their songs.
4) Do yourself a favor and do not ask to sound "louder than everybody else, and especially this one band next door" and ask to master the songs more dynamic. If you don't get why I adviced this now, you will get it when you are 30. Hopefully.