As already stated, it's better to do what you can to keep going and not stop or to get off and push. But if you do all that and still have to stop anyway for whatever reason and you really insist on getting back on then maybe I can help, I'm stubborn like that too. Anyway, this is what works for me. Others may have advice that might suit your style better.
1. Grab and hold the brakes.
2. Rotate the crank for your strongest leg just behind vertical or 3/4 back from the front, level position. You get more power if you push across the top and then down with your pedals.
4. Put your foot on the pedal, release the brakes, and push the pedal across the top and down and around while at the same time putting your other foot on it's pedal and start cranking with it, pushing it across the top too. (Don't be afraid to grab brake if things start to go wrong. It's not too late to walk. If you do, be sure and grab both brakes and lean forward so you don't flip over backwards.) Quickly put your butt on the seat, lean forward and pull toward you and down on the handlebar. You want your butt to push the rear wheel into the ground for traction and your upper body to push the front wheel into the ground for steering control. Pulling the bar towards your feet while bracing against the seat also seems to increase cranking leverage for that push across the top of the pedal stroke, giving it even more power.
If it's really steep you may end up with the nose of your seat in a rather awkward and embarassing place. Whatever, you were warned that it's better to not stop or get off and push it the rest of the way, weren't you???
