(for some reason the first time I loaded this page there were no comments, so some of this is duplicate)
Excellent! Very glad to hear it. There are a /ton/ of helpful resources out there for you. Here's a brain-dump of some of the most popular:
* CTFTime : http://ctftime.org/ : Website that tracks team scores, upcoming events, and writeups for previous events.
* CapTF : http://captf.com/ : My CTF dump-site that includes a calendar, links to "practice" sites (aka Wargames), and many years worth of CTF events archived
* Field Guide : http://trailofbits.github.io/c... : Specifically covering the skills / approaches, the field guide is a good read for anyone getting into this world.
* Guide for Running a CTF : https://github.com/pwning/docs... : Written by PPP (CMU's ever-dominant CTF team) along with feedback from the broader CTF community, this guide is more relevant when making a CTF, but can aid in understanding how the good CTFs are designed.
* PicoCTF : https://picoctf.com/ : PicoCTF is designed for high school students, but had an awesome difficulty curve, getting up to some relatively advanced challenges by the end of it. It's also extremely well designed, runs for a longer period of time and is a
* CSAW : https://ctf.isis.poly.edu/ : One of the best events targeted specifically at College students, unfortunately the qualifier round just finished, and the participants already selected for the final round, but you can always check out the archives of previous challenges to get a feel for the difficulty. Note that the qualifier event is typically intended to be much easier than the in-person finals to better encourage new students to get into the sport.
* IRC : irc.freenode.net#pwning : There's a lively and active community in #pwning on freenode that would be happy to help you with questions/advice related to CTFs.
* YouTube : There's a couple of different presentations/talks on CTFs over the years. If your'e interested in learning more about attack-defense CTFs and in-particular DEF CON CTF, I gave an old talk that's mostly still relevant (https://www.youtube.com/watch?v=okPWY0FeUoU), though I'd recommend you not focus on A/D at first, but just get into the regular challenge based or jeopardy boards as they're sometimes called.
The best way to prepare for CTF is by... playing CTFs. There's no real magic formula, just go out there and start working on challenges. Old CTFs are great as learning exercises since you can usually cheat and read a writeup, but avoid the temptation as much as possible. If stuck, go off and try another problem first, and only if you're /really/ stuck should you check out a writeup.