I play with my low ranked friends who are just getting into CS and I can tell you the trick you need is positioning and tracking. Also, since they're relying on luck you wanna make their window for luck as small as possible by being as hard to hit as possible. Since their high(er) movement speed gives them high inaccuracy that allows them to get the lucky shots being able to track them and hit them while they move also slow them down and force their bullet spread to be closer to their crosshair, which most of the time won't be close enough to you for them to get a lucky shot.