you need to list all after market electrical stuff you installed first to get some real help, so if you installed a new stereo fogs, winch, list all that stuff first. Then I would check each accessory for a draw to begin with.
I highly doubt its the ignition switch. If so disconnect it, the plug is on the left side of the steering wheel behind the upper and lower steering wheel plastic covers. Unscrew the 3? screws under the bottom cover, then remove both covers. Squeeze the ends of the large white connector going into the igntion switch and pull down, it should come out easy. Install a cheap push start from autzone for a while and see if the problem goes away.