Ehh.. alot of things. Painful to think of actually, know that starting a year later in cryptocurrency would be a huge huge deal in terms of possible gains.

• Don't base your opinions on reddit,bitcointalk,facebook posts. Research everything.
• Don't be lazy and read the fookin whitepaper.
• Don't be too impatient and use market trades. Wait the prices out a bit.
• DONT GO ALL IN ON ONE CRYPTOCURRENCY

Those are just some. Thinking of all my mistakes is pretty much like slapping myself in the face. Well atleast I've learned from them already.   *maybe*