Basically what i've been doing on a couple personal projects was to define weight painting in levels.
"level 1" -- block weights assigning vertices to a single influence. (in Maya using flood tool)
----------This was done for all skinned joints
"level 2" -- block weights of hip, major spine, base neck, shoulder junction, hip junction
----------This involved posing mesh in side view then selecting vertices need to adjust and using Maya's Add to get roughly better deformation. It was helpful to think like -- "okay i rotated this joint and its causing these vertices to rotate too much, so i need to put some weight onto a different non-moving joint so it wont move as much" Also its helpful to think about: say i put some weight onto a different non-moving joint- which non moving joint should i put it onto? This is important because putting some weight onto a different joint that eventually will get move we want it to move the area were working on okay
----------Another helpful tip especially for the shoulder and hip junction: Say were working on shoulder joint.
1. We can hold all weights except for the shoulder joint and the joint that has most of the upper torso weight.
2. Then select the vertices of the area we want to smooth (helpful if topology is looping because can select shoulder edgeloops quickly).
3. Then we can use Maya's paint tool and select the majority weight joint (the one with most white areas near shoulder) then can flood with the "Smooth" option. Note its probably helpful to do this after done previous levels because the smoothing can assign very tiny weights to vertices.
"level 3" -- block weights elbows, knees, wrists
(Also this level may include fingers and toes if character has them)
"Advanced weighting level" -- this is where weights can be carefully tweaked to get as good as can.
"Advanced corrective level" -- this is where may want to use corrective for extremely important areas like probably the shoulder.
I highly recommend checking out Michael comet's skin weighting tools. They are extremely helpful
for things like holding weights on lots of joints, and finding all the vertices that are affected by selected joint.
Inspired by Michael Comet (www dot comet-cartoons dot com)