I dont know if its been mentioned but something i'd like to add is that when i hunt squirrels with another person we usuallywalk kinda spaced out. So that maybe the first person is 30 yrds infront of the second. this way when the first person walks past a tree the bushytail will try to avoid him and move to the opposite side of the tree. this gives the second person a clear shot. i can tell ya from experience this method works great.

also (i've never tried this but call me crazy i'd kinda like to), i just came up with this . when u see a squirrel on the ground eating nuts and u try to stalk up to u and it runs away or it wont come to a call...just run at it (with the gun on saftey). this way the squirrel will run up a tree and u can shoot it. i've never tried this cuz it just popped into my mind but it should work

good luck!