☆.A.
In pre-K, my son's teacher pointed out that she thought he had a small fine motor delay. The pediatrician Rx's OT for about 10 weeks and it did wonders!
He might find it easier to write with a pencil with a grippy on it, a triangular pencil and color with nubs of crayons.
He can work on mazes, sticking round stickers into circles drawn about the same size, picking up pennies from a table using only on hand at a time, Playdoh is great for strengthening hands/fingers, as is a small stress ball.
Also things like pick up sticks, tiddly-winks, sticking stickers into sticker books, crumbling tissue paper or newspaper into balls...
Google "fine motor activities" and you will get a lot more ideas!