BACKYARD/TRAINING- Even when playing unofficially, you need to remember your BDUs, boots, and some sort of thing to hold your gear. If you have 0 BDUs, wear a pair of old jeans, a black sweatshirt, and a pair of hiking boots, or work boots. Maybe find an old military gear at army barracks or somesort for cheap. You also need some sort of safety eye wear.
PRO GAMES- Now, this is the open events, TOLCOM, GHOST TOWN, etc. There, you basicly MUST have BDUs of some sort of camo, combat boots are best,and you must [under 18] have a full facemask, or some sort of glasses. Get a vest or dump pouch, and a decent gun w/ planty of magazines and any extra gear needed, first aid kits are great.