Wow, full of great advice. The biggest one for me is: acknowledge applicants. I've hired and know what a hassle it can be, but use a system, and respond to everyone. Set deadlines, and if you miss them, acknowledge that. Look, this is a possible team member--why would they believe you'll treat them with respect when they are employees if you don't treat them with respect when they aren't?
Basically, it's the golden rule. It's not hard!