The important things to know about Uniform Circular Motion are:

• The misconception that since the speed is constant the net force must be zero. There must always be a net force towards the center.
• The net force in the radial direction is always equal to  m v²/r
• The net force in the tangential direction is always 0.
• The misconception that you must always choose the tangential direction when choosing your axis. The only direction you must have is the radial direction.