There seem to be a few people I know, and certainly a few who have spotted for me, who don't seem to know exactly what being a spotter in airsoft requires you to do. The way I see it, from originally being a spotter myself (still do it from time to time) and from being a sniper and knowing what I want from a spotter; is as follows:
Responsibilities of a spotter when on the move:
-Being in front of the sniper while stalking, since you have a better close range weapon, is always a good idea, unless you are very inexperienced at leading and watching carefully.
-You should stop and look through your binocs at anything that moves in an unnatural way.
-You must be ready to lay down fire hard and accurately and with confidence should you be detected, and by 'with confidence' I mean, standing your ground until your sniper has retreated far enough to be at a safe distance to cover you while you retreat.
Responsibilities of a spotter once position is reached:
-You should call out targets for your sniper as you see them.
-You must keep an eye on your surroundings. Your sniper will not be as aware as you; it's very easy to get tunnel vision and focus on your current target and nothing else if you're staring down your scope.
-The most helpful thing, however, that you can possibly do with regard to firing, is watch where your sniper's shot goes with regard to the target, and then tell him so he can adjust. It's also useful to know your sniper's rifle, so you can advise him on where to aim or adjust his scope for longer distances, and approximate the wind direction and speed so he can adjust for that. (quick tip for snipers here, rotate the rifle in your shoulder (muzzle should still be pointing the exact same way) to adjust for wind. The hop will throw the bb against the wind. Obviously you won't get as much range, but you'll have a better chance of hitting your target than if you aim to either side and let the bb be carried back in by the wind) Telling your sniper where his shots are landing is possibly the most important thing you can do.
-Always keep an eye on the enemy. Watch for if they have seen you and how close they are getting. If they have seen you, return fire! The further away they are the better since you're not looking for hits you're looking to get you and your sniper out of there ASAP with as much distance between the enemy and you as possible.
-You should be in charge of communicating with your team. Give them regular reports of what you are seeing with regard to objectives and enemy movements. This will aso help your sniper, because having repeated to you audibly what you are seeing is calming and helps you to focus
-You should be the one judging when it is time to move, since you are in communication with your team and know where you're needed, and you have a better field of view than your sniper for deciding when it's too dangerous to stay put.
Hope this helped all you spotters (and snipers- remembering what you should be doing too!)
Jim