When I was a team lead, I found that one of the best motivational tools I had was a chocolate chip cookie! (well, one guy didn't like chocolate chip - he got oatmeal raisin)

We had a store that sold fresh baked cookies downstairs. If someone did something that took a bit of 'extra effort' - or even met a milestone that we all knew they could make, but made sure they did it, they would come back from lunch, and find a little bag with a cookie on their desk, and a quick note from me "Thanks for XXX". It was basically a nice way to say "I noticed you did this, and thank you"

I set the goals (in my mind) low enough that most folks were going to get a cookie a week or so - sometimes more, sometimes less. I also made time to spend say 5 minutes a day at everyone's cube, as say "You having any problems, anything you need me to do?"