I reserve the right to change my mind on “most important” at some point, by the way.
Right now, though, these are the two most important skills a good blogger can develop:
1. The reconciliation of limited time and (nearly) unlimited information. The skill of determining on the fly “this matter, this doesn’t, let’s tie those three things together, scrap that, etc.” is everything in blogging.
2. Connecting the dots. I’ve written about this before but to be able to consume the aforementioned unlimited information and connect the dots between three or four things so that you’re able to string a story up on the Internet is why great bloggers are great bloggers.