You didn't mention what gun or action, but in any case, remove the trigger and anything else attached to the bottom of the action, and fill in the recesses with modeling clay, and smooth it out...
First though, check to make sure that the barreled action is sitting centered in the stock, and make sure the action screws are not touching the stock...
Since you are going to glass bed the action, I would think you are also going to install aluminum pillars, which is definitely recommended...
Since I do a lot of filing of stainless steel parts on one of my lathes, I save those small shavings and add them to the Brownell's Acra-Glas Gel on certain bedding jobs, to add extra strength to it...
My favorite bedding material though is Marine Tex!
In bedding the recoil lug, bed it tight except for the very bottom. You want clearance there...
And like has been said, don't forget the release agent! You can also put some on a Q-Tip and rub is along the top edge of the stock to make removal easier. Just before the bedding compound gets too hard to work with, you can remove the gun from the stock and "fillet" the bedding compound off the top edge of the stock. Once you have all of that done, put the gun back in the stock, tighten the stock screws, and let the bedding compound finish curing...
Any questions along the way, just ask!
