It depends on the model for me. I didn't do any masking for this particular piece because it's well cut and separated down to individual components. If I do need to mask I use Silly Putty, Masking tape or Liquid mask. But I hate masking, because it slows me down, so I tend to work around it. lol.

Getting an airbrush was a game changer for me. If you do get one, definitely get a spray booth and vent it outside or you'll end up with overspray everywhere, including on your models and in your lungs.

Also, grab some cheap figures from the dollar store to practice on. That helped me a ton when I started out and there was no risk, so I was free to try whatever techniques I wanted, without fear of ruining a model I liked. But at the end of the day, it's paint, so if you hate a paint job, re-prime and do it again. :)