I think whether he's interested or not depends on how you behaved during the date. Did you do any of these things:
* Compliment him on something physical about himself (wow, I really like your hair).
* Casually touch him. There are a number of ways to achieve this without being awkward. You can wear heels so you have a reason to take his arm, be slightly underdressed for the weather so you can snuggle, or you can brush against his shoulder or leg.
Basically, if you're interested in a guy, your job on the date is to communicate that you're interested without explicitly expressing interest. So in the end, he'll feel like it's his idea even though you've given him the opening.
In terms of contacting him again, it can go either way. But if you're the one to initiate contact, the important thing is to be casual and communicate that hey, you're interested but you're not hung up and have other options. I tend to do this by suggesting we keep in contact even if he's interested in just being friends because we had a good time. Usually either the guy says, cool, let's be friends, or it forces him to let you know he's interested in dating and you're good to go.