What i've found that I use for my workflow is that I use the componant editor to sort out sections of the model, i.e if the left legs verts are controled a bit by the right fingers then use the componant editor to set the weights to 0.
When I go into the paint weights sthen I only ever add, never take away, what I mean is say if your doing the knee, then only add to the verts, if you go over what you need, either undo or select the next joint, in this example the ankle or hip then add a touch to that vert (as if you add to the hip it will take away from the knee etc)
The point of only adding is that they need to add up to a value of 1, if you only take away then maya will add the extra to another vert somewhere (at thats my understanding!)
Hope it helps
"No pressure, no diamonds" Thomas Carlyle