What's the #1 thing people are afraid of? Public shame. I have a theory that Scrum primarily works because of this. Just have daily Scrum-light meetings with your group. If you have 15 minutes with a group of 5-6 people and everyone has to say either "done" or "not done"... the not dones will of course have some silly excuse, but because of the time constraint you must cut them off, be curt, and say to the effect "so John can you help Dan with that right after we break?". And then everyone would make commitments on to what they would do that day. I guess in a way you can say this was being a drill sergeant, but the thing was I wasn't an a-hole, that 15 minute meeting every morning was just part of the process, it was expected.
After a few weeks of this everything moves at twice the speed. I had a team of 6 devs (including myself) burn through nearly 200 bugs in 2 months. That's every engineer fixing about 4 bugs a day. There was a hug chasm of talents on that team... we had the top guy in my dept as well as one of the weakest engineers on the same team. Everyone performed.