It's a skill you learn with time. You have to be able to walk point in a way that will spook ambushes and snipers but not get your point man shot out to fast. Then you should try to fan out and around the suspected snipers position. You can take your time doing this being cautious for more snipers, as the first wont likely move. Also if your not worried about making to much noise allot of newbies snipers will fire back if you do a simple recon by fire, giving there position away, but the more experienced will just be clued in that you have no idea where they are.
If you are short on time you might have to fan out and around more quickly. First try your best to judge if there are more people around the sniper or if he is there to delay you while a larger force takes a different path. Good communications with your team or just listening for gun battles can help you to decide this. If you believe he is alone you can send out two teams around on either flank fast and at both times. Using lots of suppressive fire once the sniper opens up. The majority of snipers will open up when this happens with a solid stream giving away there position. The really skilled ones are harder to get at.
Also when snipers are used to slow your team it can often be worth losing a few bodies and just plowing through them, as this is one of the most common and effective way of corralling people away from a safe area and in to a kill zone.
If you ever do pass a sniper with out eliminating him, and must continue on, leave someone to watch your back trail so they don't sneak up on you. This also can freeze a sniper who will have a hard time moving.
tl.dr Use point men to spook out snipers and try to get a fell for the bigger picture and roll of the sniper you are currently facing.
This post has been edited by Fallout: 28 August 2008 - 09:35 AM