How do I stop kitchen cabinet handles from spinning? I screw them tight and they just spin after a little use

Maybe there is a special washer or something? These are the single knob cabinet pulls.

put some liquid lock tite on the threads first
Well, the handles could just be old and the part where the screw comes in might be worn, and that would explain why you can't tighten them without spinning...Why don't you try replacing them?
Loosen the knobs all the way and put a drop of clear nail polish on the bolt threads. Reassemble while the nail polish is still wet.
locktite will work nicely. only put a little bit, though! also, if you don't have any locktite, you can use a drop or two of iodine on the threads. won't hold as long, but does quite well!
Add a lockwasher. They are cheap for that size and you can get them at any hardware store. Take one of the bolts (screws) in with you so you get the right size.
You should be able to buy some simple washers with little "teeth" in them, they will grip the wood of the cabinet better.
I like the nail polish idea, but if that doesn't work, put a little plumbers thread tape on the screw. You don't want to use glue or you will never be able to get them off if you decide to cange the handles.
locktite works well, but they make different strengths of locktite. Do not use one that is too agressive or you may not get it apart if you decide to change them