Get some new brake-shoes. Buy quality, not the cheapest you can find (NOS is best, if you can find it).
Then degrease your brakes with brake cleaner, get it really really clean. Then take some grid 400 sanding paper, and softly sand the inside of the drum (Sand in the rotation direction). Then clean the drum again with brake cleaner.
Then softly sand your new brakepads with grid 400, in the length, not width. Then clean your new pads with brake cleaner.
Install, and set them up so that you can't pull the brake levers to the grips. If your brakes are going heavy, lubricate the cables or get new cables.
This should get you stopping on a dime. (Well, not really, but you won't need your feet stopping from 50 :P)
If you want real braking power, build a disc-brake on yuor front wheel. But that's a lil more work ;)