Hi I'm Fedex202 and I am going to tell you basic classes, and keep a look out for my advanced classes guide.
Step 1: Riflemen, the Work Horses of Your Squad
Rifleman, the most common role of airsoft and the work horse of standard airsoft. It isn't uncommon to find entire squads of them, well with one person acting as the leader.
Weapons Type: Electric, some spring
Kind of gun: Assault Rifles, Rifles, Big SMG's ae: UMP 45, P90
Optional Weapons: Grenades, Under barrel grenade launcher, red dot sight, and other attachments, Pistol (Recomended)
I judge clothing in three levels: Beginner, Into It, and Pro
Beginner: Darker street clothing
Into It: Camo, a equitment belt with ammo pouch or thin to hold 2-3 low or mid cap clips or 1-2 High cap clips, and a holster for your not required but recommended pistol
Pro: Every thin that "into it" has but time six, like face paint and stuff like that, helms and stuff thats close to the real deal
Step 2: Sniper: One Shot, One Kill (patience Required)
Ah, the patient sniper, waits for its prey and a good sniper will wait for just the right moment. A good sniper might only fire a couple bb's a round, so if your a "Heat of the battle" kind of person the sniper is not for you.
Weapon: Sniper and for this class a pistol
Beginner: Camo top and dark pants (durable recomended) and a hat that you can put leaves and branches (optional)
Into it: Ghilly suit, or clothing that you can put leaves and branches it and a hat with leaves in it, or a cool decked out mask like www.instructables.com/id/Ghillied-up-make-your-own-ghillie-paintball-mask/
Pro: Gillie suit and your choice of belt and mask
Step 3: Scout, Time to Run and Gun
This class is kind of a "Run and Gun" kind of class this class will need to be fast and versitile. This class may use the most ammo in its "spraying" of pellets at the because of its inaccuracy.
Weapons: Small SMG's ae: Uzi, MP7, and/or very rare but electric pistol with semi, auto, or burst
Helpful things for this class: spare mags, and ammo
Beginner: light clothing stuff easy to run in
Into it and Pro: Light camo and a belt for ammo etc, again easy to run in.
Step 4: Thats the Basic, Go Have Fun
This was my basic guide, and if you like this Im coming out with advance class guide and tactics gametype guides.