If that happens, then don't approach the same spot too many times. I know it sounds tedious, but it's what I do, and it usually works well if I can approach from either a different angle or even a different route entirely. Many top tier players do this as well. All I would say is practice being able to locate snipers more quickly. Maybe even try sniping yourself just to know where they might be sniping. I used to think snipers were annoying too until I learned the patterns they use. Best of luck to you.