Sort of a simple guide to see if your pelt is one that can be mounted or not properly. I'm seeing so many pelts that people have attempted to mount up that really should not have. Practice is one thing, but practicing with the proper materials/pelts will help far more.
If you want to try your hand at taxidermy, start slow and gather up the right things. Squirrel kits are fairly cheap, as are craft faces (coyote/fox/etc.) that you can try out hydrating, repairing rips, turning ears/lips/etc (only if they are present!) and so on. Use oil clay on a cheap form to practice sculpting eyelids and more and watch as many mounting videos as you can. Work your way up till you are ready rather than jumping right in and ruining a pelt that may, or may not, be mountable.
Proper forms will give you the right shape as well as all of the key marks you need to have things line up right and using the right adhesives and clays will ensure a long lasting mount you can be proud of.
A note on the extras at the bottom:
With leather, take a little and test it first. luke warm salt water is what I use. Just take a little from an edge and let it sit in the water for 15-25 min max, checking it every 5 minutes after the 10 minute mark. it should stretch a little and not tear immediately. if it tears easily, don't hydrate the rest or else you will risk dry rot and things falling apart.