Developing fine motor skills is so important to children's ability to hold the pencil to write (and for cutting). Here are some of the ways to develop this. Certainly, there are many more ways but use these as starting blocks and ideas.
The younger the child, the larger the beads.
Colouring with crayons
Cutting with scissors
Cutting wooden play food
Pegs and pegboards
Wooden puzzles (with pegs)
If you need to buy your own, here are a few you could try.