Clothes made of black vinyl are a big key for getting into visual kei; it could be pants or jackets, this is VERY much optional; but i also notice they like to reveal certain body parts and then completely cover others, so you could combine short tops with big bottoms or short bottoms with covering tops!! I've also noticed they like to use (ether rarely, often, or just ocasionally) corsets and ripped/uneven puffy skits with layers! Accessories like fishnets, chains, and choker-like accessories are also recommendable in my opinion!!
As for the crazy hairs, you can keep your real hair simple and use wigs for the crazy stuff! It helps to not damage your real hair :D (plus they're easier to style since it's almost like you're styling on someone else's head rather your own, but if you wanna go ahead and do so on your own that's still nice !)
I'm not an expert but i hope it was helpful-!