First and foremost, make sure you don't cheap out on Eye protection and on Boots. Paintball masks are fine, but if you're looking for ballistic goggles, make sure you get good quality ones. Same with boots. Pick a pair that your feet are comfortable in and have plenty of ankle support. Outdoor games can have uneven terrain and ankle support will really help.
Usually G36 mags will fit in a double M4 pouch if you cut the elastic retaining band that sits on the outside of the pouch. It works well for me. They take two hands to insert but can be pulled out smoothly. If you have a dump pouch it makes it easier as you can toss the spent magazine in there and reload/reinsert when you have the time or are back at a spawn.
I just played my first game with a hydration pack on the back of my vest. It really simplifies things and i highly recommend it
H&K G36c (KWA) / Glock 18c (TM) / Kimber LAPD SWAT Custom (TM) / Mossberg M500 (ACM)