COSPLAYERS: Tips on sealing paint?

Hi! I'm very new to the Homestuck Cosplay scene, and have practically 0 experience with makeup outside of lipstick and blush.

Can I get tips for sealing my Mehron Creamblend Stick? I bought the colorset powder from them but sometimes It's just not fully setting and I'd rather not cause an incident when I do eventually wear this in public for the first time. Am I just not applying enough? How do you seal your paint? What's the best way to test and make sure everything is sealed?