When you do start attempting to handle your snake, be sure to give it a few rubs along its side to let it know you are there. Sure they may squirm and wiggle away to go hide again, but it will let them know further down the line that if they get rubbed, it's not a threat to them.
That way when they start becoming used to you, the rubbing will signal that they will get picked up and handled. Then they know what to expect beforehand without needing to freak out and find a hiding place. Consider it a knock on the door before coming in.