Save up for quality equipment, learn how to use it, lots of resources like Skateperception or just by trial and error. Torrent premiere pro and after effects. Film your homies and have fun. Filmers are generally pretty happy to help each other, give advice and what not. Once you get into it, filming is pretty fun, though very frustrating when trying to film a clip for hours on end.
Get used to skating around with a heavy ass backpack, having to put it down everywhere, taking ages to set your shit up, thats probably the worst part about being a filmer/photographer. You'll be saying "next try bro/you all good man/you got this" a lot. Also try to make sure your posture when you're not filming is as good as possible, filming really fucks your back up, especially if youre 6 5 like me.