+1 to what MandShef said.
I would also add that it's important to keep relaxed. My teacher's noticed that when I'm tense my bow position moves closer to the fingerboard so I have to consciously relax my shoulders. Makes bowing easier too! I try and bow about an inch or so below the fingerboard and have raised the bass so that the bow natural touches the strings there.
Also the A string is bowed slightly faster than the E, the D string a bit faster than the A etc. Exactly how fast depends on bass, bow, strings and what sounds good to you. (That's before you get into fitting your bowing into the piece you're playing!)
Bowing is one part of DB playing where having a few lessons can really help. It's certainly one of (many) technical aspects that I constantly work on.