Motivating a team that has low numbers.

Coach--we have the same situation as you. Last year we had 25 kids with only 2 sophs. Competition for positions is fairly low and it is hard to motivate the kids to do the extra things that an athlete in a bigger school would need to do in order to win a starting position. But we still try to motivate. Here are some of the things we do:
1. In our opening weeks of the season we divide the kids into teams and at the end of practice we have the teams compete doing non football things like building a human pyramid, relay races, etc. At the end of a day or week we had a reward for the winning team whether it is giving the winners a conditioning break or popsicles, etc. The kids get excited for it and it fosters a good competitive edge.
2. We offer player of the week tshirts for varsity and jv games. We don't have set criteria and just leave up to the vote of the coaches that way even the waterboy has a chance of being POW.
3. We have a pretty harsh "makeup" conditioning activity for a kid that may miss or be late for practice. We call it run bear run. They sprint and then we blow the whistle and then they bear crawl blow the whistle they run, etc. A couple hundred yards of this and they either quit the team or finish. We have them complete this in front of the rest of the team and as they do it we give the speech that we need everyone to succeed and by not showing up they are letting the team down. Bottom line, the rest of the team sees the pain involved and will think twice.
4. We give them positive feedback everyday after practice as a team. I guess overall we incorporate the idea of family. And that we can't let the family down. Works for us. If you have any questions let me know.