Mount it like a sane human being.
Seriously, I've never had one that wasn't.
What I do is mount the scope mount on the gun (if applicable), put the gun in a vice with some rags for padding, level the gun in the vice, install the scope rings, check for level on the rings, set the scope in the rings, use the turrets to level the scope, slowly tighten the rings, alternating screws to even the torque. Done.
There are certainly much more complicated ways of doing it. There are expensive tools for doing it. I have always used this method on every gun from my 10/22 to 12ga to Encore handgun and many others. I have never, NEVER, had a problem. The scopes stay locked down, they shoot straight, they don't get bent or scratched....
Fancy methods and tools are more of a gimmick than a necessity. Frankly, even leveling the scope is unnecessary except for the longest shots. Even with a leveled scope, it doesn't help unless you shoot with the gun level.
