I've never put extra air into the tubes, although I use plenty of talc or baby powder. I always inflate the tube a little, even a brand new tube, and dunk it in a tub of water just to be sure there are no leaks. In 30 years I've had a couple bad new tubes. Then I pull the core out of the stem, dry it off and make a mess with baby powder.
I use the tips of my irons, just over the edge of the rim (rim protectors on my nicer rims) and just make sure the opposite bead is down in the relief channel. Take a small bite a time. When you're starting out, it's nice to have an extra set of hands to keep the bead down on the opposite side. If you're sweating or forcing it, stop and have a brewski, and come back in a little bit.
Good luck, it's still more work on the side of a road or up a trail, but having done it plenty of times at home you'll have the confidence to git er dun!