The longer you work at it, the more flexible and stronger your hands will get.
When I started, I couldn't do several moves. Charlier Cuts were barely possible, scissor cuts were impossible, a one-handed shift was the stuff of dreams. After a year of solid card work, I could do most of them with no trouble. At this point I can do stuff like a one-handed shuffle and one handed cuts, one handed second deals (I like one-handed techniques). All it comes down to is working until your hands can do it.
Entirely off-topic, but I have a friend who has gotten me to teach him only one handed techniques. He does no performance, gambling, or magic of any kind. Just likes to have something to do with his hand. He can do one handed bottoms, seconds, greeks, faros, false faros, and a false charlier. It blows my mind.
Anyway, Jason's tip to use only about 2/3 of the deck when starting is extremely helpful. Another trick I used, I thought it helped, was practicing the move upside down. Simply turning over your hand and attempting to execute it. It results in a lot more mistakes, but also lets you figure out the grip a little quicker, which was one of the hardest parts for me. Another tip is stretching before you practice the bottom deal. I like using D&D routines for stretching, but just playing around with your hands absolutely works. Lastly of course, practice. It takes at minimum about a week to get any sort of feel for a bottom deal, much longer to really get the hang of it. Thankfully, once you do it is both fun and easy to practice.