In order to have success on the leaf hatch, you're going to need a larger size hook, anything size 12 & up should work, which will really help you in not losing your leaf during the fight. Fortunately for me, this rarely happens & I usually bring each leaf I've hooked to hand.
Another key to success for angling the leaf hatch is to make sure you're fishing the proper section of water. You're going to want to inspect the trees & bushes along the bank for signs of a hatch. It helps to know what to look for. For example, in the photo below you can see that there's a group of leaves about to fall into the water. Down stream from here would be a good place to wet a line:
Here's the really important part: when you feel the tug from a hungry leaf grabbing your fly, yank your line as hard as you can - as if you were trying to set a hook into concrete. This way you can hook the leaf properly & it's certain not to get off the hook before you can bring your leaf to hand, ensuring your success.
I've found the best place to hook a leaf is at it's base, near the stem, like I did to this monster:
Good luck on the water out there. I hope you're all still enjoying some great autumn fly fishing!!