I’m really not good at this!  I try to get better at it all the time.  When I started taking on other work on top of the comics site, I realized that I could only have 2 or 3 things on the go at the same time, and that was an important thing to figure out, because if I have too much I can’t concentrate on anything and the work is garbage.  You need to find out what your limits are, and how to work within them.  Also, everything my nephew does is amazing.