After 10 years of doing this, 5+ fulltime I will say the biggest 2 things I found are
1. Manage your emotions
2. Have a Risk plan and follow it, I do $4 profit for $1 a risk and win over 50%.
Read this if you want to see how I trade, it's over 60 pages and someone took the time to put all my posts into a Ryanmcd.doc. and now others trade the way I do..
http://www.forexfactory.com/showthread.php?t=163972
I just read about 10 pages of that thread as well as Ryan's word doc that was attached to one post. I don't think I understood a single term in anything I read. I dunno how you guys learn this stuff! I spent a lot of time reading links that Steveny has thrown at me and I don't even get much of that... Forex is like speaking in ancient Sumerian.