C has two sounds, hard like 'cat' and soft like 'city'. At first, teach only the hard /k/ sound. The soft /s/ sound depends on the next letter and confuses early learners. Save the rule for later: C says /s/ before E, I, or Y; otherwise it says /k/.

C is one curve, one breath. Pull the pen in a single arc. If it shakes, slow down. The smoothness comes from confidence, not speed.