Perhaps it’s hard to control the pencil. Coloring within the lines isn’t quite happening. Rather than doing it again and again for practice, let’s step back.
Here’s an activity that has much of the same components, but is child focused and can be fun and less frustrating.
Get a car playmat (or make one, if this is something you’d like to do). Sit with your child to play. Travel on the roads with the cars and trucks. Don’t like trucks? Take the toy animals on an expedition!
Talk about staying on the road. Talk about the things they might see. Be careful not to take over. Try to follow their lead.
You can do the same with a wooden train set that has grooves: those guide your child to stay on the track.
How might this help? It works on hand-eye coordination, on following the lines, and can provide practice for crossing midline. The general idea is to always start where your child is and work from there to where you want your child to be.