Switches on their own don't actually need to be groundedto function. Some like to ground them, but I never have.
It's easiest to have grounds "flow" in on direction though, makes it cleaner to follow and sometimes has a better result.
*All pots are self grounded to tops.
*Pickups grounded to volume (farthest away from jack)
*Connect volume ground to first time ground (getting closer to jack)
*Connect tone 1 ground to tone 2 ground (even closer to jack)
*Connect tone 2 to output jack.
That way all the grounding will flow out in 1 way.
As for the ground wire from the bridge (ex tremolo claw) it can be grounded where ever alone the way out, but may as well be the volume pot since it's already got the pickups in it too.
Now for the switches to be in the off position, or even perform a coil split, sometimes they ground a lug in the configuration to kill the current in that pickup. But that's different then grounding the switch.