I practiced falling from my bike onto an inflatable mattress on the grass in my backyard.
Then I took out the mattress and fell on the grass.
When I actually did fall in the gravel, I didn't break any skin.
Never catch yourself with your hands or elbows; try to land on your hip and roll to your back shoulder.
My husband laughed at me, but when he fell three weeks ago, he stiffened his arm, caught himself with his hand, and now cant lift at the gym due to shoulder pain.
Even if you never fall, you will have the confidence to know that it will not hurt if you need to cascade off the bike at zero miles an hour. So much more of an embarrassment then physical injury.

I loosen my clip for the first year until I was very comfortable with clipping out.
Good luck, and yes, it does help with going uphill, but it helps more with fatigue than anything else for me.