Add security to registration form for online game

I have a browser game ([login to view URL]) that needs increased security during the registration process. I would like to start by upgrading the registration system to add an email check/confirmation (they must click a link in their email to confirm it is legit). I also want to add an IP check to make sure no one has registered from the same IP within 3 days. I would also like to add an IP blacklist so that no one on the blacklist can register. If there are other ways or better ways to increase security and keep players from registering multiple accounts or to keep bots from constantly creating new accounts, I am open to suggestions! Please don't hesitate to ask questions!