Tips and Tricks
Information on Weight Painting in the Blender Manual.
Let me know if you have questions about the tips below. I would also be curious if you know of any good tricks that you don't find here. I will include them for other users that come to this page.
Show the edit bones, by enabling layer  in the armature data tab. The default control bones are on layers [0-3].
Select vertex groups through deform bones!
1. Go to Object Mode
2. Select first the armature object
3. Then the Mesh object.
4. Go into Weight Paint mode.
You will be able to select individual bones by holding CTRL and clicking on them. You can select multiple bones, by holding Shift and clicking on them.
However, this vertex group selection mode is disabled when Selection Masking is active!
You can edit weights by selecting bones.
Quickly edit weights by choosing an operator from the
Weights menu in Weight Paint mode.
Choose for example the
Smooth operation to run a smoothing pass over individual or all vertex groups. If you selected one or multiple deform bone then you will be able to apply the action to the associated vertex groups.
Select all lid bones and quickly smooth their influence by choosing the Smooth operation and selecting the Selected Pose Bones option from the Subset dropdown in the Smooth operator options. You can apply the same workflow for all other deform bones!
Completely remove influences from objects by deleting the associated Vertex Groups.
Quickly removing non-lid weights from the eyelashes, by deleting unlocked groups!
Example above (removing non-lid weights from eyelashes):
1. Filter for specific group(s) (e.g. lid)
2. Lock all vertex groups.
3. Delete all Unlocked Groups.
4. Unlock all remaining groups.
You are left with only eyelid influences. Now you can go on by running a quick smooth from the weight paint menu.
DEF-face influence = rigid area on the main face object
The bone DEF-face is used as a mask to remove weights from geometry outside the face. It does not move, so all vertices that are bound to it stay in place. You can add weights to it (with Auto-Normalize activated) to add rigid areas or smooth e.g. the neckline on Jaw open expression.
Quickly visualize and change weights for individual vertices. You can also copy the weights from the active vertex to other selected ones.
Try the Corrective Smooth modifier for quickly and non-destructively smoothing the weights.