Liquid nails is awesome strong glue, I didn't know they made it in little toothpaste tubes. It's harder than cement when it cures.
When I use Elmer's, I actually do it pretty sloppy. I just squirt a little blob under the label. Then I use my finger to press the label down which will cause the excess glue to come out from under it. Then I use a different finger (with out any glue on it) to wipe off most of the excess glue. Then I use a cloth to wipe the rest of the glue clean from the label.
I know it's sloppy as hell, but it's just my lazy ass way of making sure there's enough glue and that it's evenly distributed under the label.
And again, I've used Elmer's for a few labels now and they're still held down after some years. Some of which are in a basement room which is damp and whatnot. I feel Elmer is strong enough glue to use, anything stronger is over kill.