The go-to solvent for this procedure has traditionally been anhydrous acetone. Get an appropriately sized glass container but not so large that you are only using the bottom half or third of the vessel.
The idea is that you want to dissolve all your product in the least amount of liquid possible. You want the solution to be super saturated. This is where good lab techniques are required, and that sort of thing gets better and better with practice.
Once you have you vessle full of this pregnant liquid, put it in the freezee, leave it there and don't shake the freezer, dont bump it, dont run on the treadmill, dont vibrate anything.
Again, technique and skill are needed. You want the acetone to evaporate as slowly as possible to encourage larger crystal arrangements. But you want to keep out any humidity/moisture. That's not easy in a freezer or refrigerator.
The rule of thumb is the colder the process, the larger the crystals. The slower the process, the larger the crystals.
None of this will purify the product unless you use a (vacuum) filter process after making the saturated solution but before the recrystalizing stage.
Pure meth does not like to make very large crystals, so be ready for some level of disappointment.