My average return is 10%~30% over the course of a year (I've had a couple of years with a 50%~60% return, but that was just the luck of the Irish).
My winning rate goes from 40% to 60% (you can still be profitable with a 30%~40% winning rate).
My maximum drawdown has been 10%, but generally is around 5%~6%
My longest losing streak has been 4 months in a row. Not easy sitting in front of the computer for 4 months losing money non-stop.
The key is risk management (lose a little, lose a little,... you win a lot type of thing), and staying faithful to your system no matter what.
Basically, you have to become a robot, and leave your emotions aside.
I started trading in 1999, right before the Tech bubble. Before that I was a long-term invertor.