1) I don't actually use the switchable action bars during combat. (Mazumok has various tracking options and aspects on his action bars, but I rarely switch to that bar.)
So, I unbound Shift-1 through Shift-6 from action bar switching, and bound Shift-1 through Shift-= to the bottom left action bar (above the standard number bar). This has been a huge win for me. I'm able to invoke many more functions in combat without the pause to find the the mouse pad and hunting to mouse over the correct icon.
It's possible that I should go one step further and unbind Shift-Up and Shift-Down. It happens too often that I accidentally switch action bars and waste several seconds hitting Track Hidden instead of Hunter's Mark.
I also usually try to keep the Shift-
- For Maz, I have my basic melee attacks, Raptor Strike and Wing Clip, on 1 and 2, and I've added Mongoose Bite at Shift-1. (I don't have 'attack' on Maz's action bar. If I'm so low on mana that I can't Raptor Strike or Wing Clip, either I'll survive until I regain some mana or remember the 'T' key, or I was probably going to die anyway.)
- For my cloth-wearing spellcasters, I have 1 bound to 'Shoot Wand' and Shift-1 bound to 'Melee Attack'.
- For Mahotala, 9 is Healing Stream Totem, and Shift-9 is Mana Spring Totem.
Having these buttons be special has meant that I've been focusing on using them more efficiently than before. It used to be that I had all my long-term buffs in the lower-left corner. These have moved elsewhere (to the bottom-right bar, usually).
This has had a particular effect on Mahotala, my shaman; with this reorganization (and finding more totems and effects I wanted in my action bars), I didn't have room for all four weapon buffs. I've decided to just put one weapon buff on the action bar (in the shift-1 position) and re-evaluate which buff should go there when I switch weapons. (Perhaps I should make or find an addon that calculates the ideal buff to use, and use that.)
2) I mouse with the right hand. Therefore, functions I need to use in conjunction with the mouse go on the left hand.
The particular case where this comes up a lot is with targeted area-of-effect spells. For example, the previous sequence for casting Blizzard was this:
a) Hit 8 with right hand.
b) Shift hand to trackpad.
c) Move mouse to target and click.
Now that I've moved Blizzard to key 5, I can do steps b) and c) at the same time as step a). This too has been a big help.