There's advice in this Alexander Chee piece on The Awl for writers at every stage of their careers.
I worry that you guys worry about #21, for reasons that are perhaps obvious.
Which one of these are you guiltiest of?
I vacillate between #16 and #17, personally, so now is as good a time as any to do a shameless plug: tell your friends about this blog! If we can get to 25 comments on this post, I'll do a critique contest later this month.