Sanitize Santize Santize. Then when you're done, Sanitize some more.
Actually, one of the things that has helped me the most is having absolutely everything ready to go. I put all of my hops in different bowls and label each bowl with a post-it as to when they're supposed to be added. I have all of my equipment in a StarSan, waiting to be used. I also prepare my process beforehand and have a large bowl for my brew in a bag, etc. Going through the process before you start will help you after you get underway. That way you don't have to scramble around looking for this, or that, or how much of this to add, etc.
Good luck!