Basically do a little researches on the styles that people are currently using (and wining with) in mixed martial arts competition. These days, most of the mma guys do not adhere to a particular style. They incorporate the best moves from each of the styles to make a hybrid style. Think of developing moves in each of the
ranges of fighting.
Striking Range
Boxing skills are damn near a necessity. Kicking and kick defense skills are as well. Muay Thai and western boxing cover everything that you would need.
Clinch / Takedown
Slightly closer than striking range. Mauy Thai is absolutely vicious in this range. Clinching with knees to the head! You also need to be able to takedown opponents and have the ability to ‘sprawl’ to avoid taken attempts. Wrestling is best, but skills can be learned in other systems (Brazilian Jiu Jitsu).
Ground Fighting
You need skills in gaining dominant positions, submissions and chokeholds. I’d highly advise Brazilian Jiu Jitsu because it is still in use in most mma competitions, but is actually
more effective in the street. The reason: in mma competitions most guys fight in shorts (at most). In the street, most people have clothing on. BJJ has many chokes that involve the use of a ‘collar’ or clothing.
Remember to train like an athlete would. You can never have a good enough cardio system. Think about training for shorts busts of aggressiveness. Do a search for HIIT. Do not neglect strength and flexibility either.
These guys will answer a lot of questions that you have specifically about training.
http://www.sherdog.net/forums/index.php?
Scroll down to the ‘Training Discussion’ sections. There are enough quality people there that will flame anyone who tries to give bad advice. Lurk for a while until you begin to recognize the difference between the keyboard warriors and the guys who actually know what they are talking about. Once you begin posting, ignore the keyboard warriors.