Im still new to Flying,but the first few times I took my plane up I used my thumb to control everything. It seemed that everytime I would place the input on the control like up on the elevator, I would also accidently be placing either right or left on the rudder too. Which caused several crashes. Ive started using my fingertips now and have a whole lot more control over my flight. I still crash sometimes but not as much as I did the first few times.