My child has had OT therapy and here's the things our OT has suggested:
1.) use tongs for strengthening the hands. Make it a game, either get cotton balls or buy some squishy type bugs or something he likes that is squishy and have an empty egg carton. Have your child use the tongs to pick up one by one the cotton ball or squishy bug and place 1 in each of the slots and then take them out.
2.) Buy theraputty. It is a therapy grade putty-strengthening putty and there are exercises that go along with it. You can put pennies or other small items and then your child has to dig and find the items in there.
3.) use pencil grips or pen grips to help with the grip on the pencil. Get a special pen.
4.) Games- Topple and Perfection. Both of these games have little handles on the pieces, so you have to pick up the pieces with your thumb and first finger. This is something fun that you all could do together.
Catalogs- 1.) fun and function- has great products for fine motor skills.
2.) mayer-johnson.com - Dynavox has a few things for fine motor in there also.
After all of this, if it doesn't get better, schedule to see an OT at school or in private practice.