There's a bad advice here. You should have proper monitoring and a proper room to mix in. If you're not aware of what's going on, how can you fix it? A mix made with proper monitoring will sound good anywhere, headphones included - and that's the whole point!
You should take your time to perfect your mixing skills better. Don't even worry about "mastering" until you have a lush sounding mix in your hands. The mix is where the gold is. I think it really helps to have a grasp of such things as: gain structure, mixing with groups, parallel processing (much needed in any EM genre), mid and side processing. It's good you had piano lessons, you don't need to worry much about music theory, right? Learn your synthesis, make sounds while having in mind where do you want them to sit on the spectrum and on the stereo stage. Think 3d.
Take your time to really learn your DAW to.
EDIT
It's easier if you'd place a sample of one of your tracks for us to listen to. I'm sure there's some good ears round here that can give your more specific tips
I have this subscribed on youtube: dubspot.com. there's some good production techniques on display there (that's why I subscribed it) and they sell courses to.