I have been doing prewriting activities with my daughter for a few months because she seems to really want to write...she gets VERY frustrated when she says she is going to write her name and scribbles instead!
We have been doing some Montessori inspired grip-strengthening activities like clipping and unclipping 'chip clips', or clothespins, on the side of a bowl, and strangely enough, found an app called Bugs and Buttons where one of the activities calls for you to 'pinch' a bug on the screen and drag it to a jar! In just 2 weeks with a few minutes of play every couple days I have seen improvements...
We also have triangular crayons and pencils, but my daughter is addicted to markers...I ended up buying the very thin markers and putting those rubber triangular grips for pencils on them. It works really well, and she has always held a writing implement quite well, even without grips...
I just found a letter stencil, where you put the hard plastic tool on the paper and trace inside of the stamped out area...we did this first with large cookie cutters, then smaller metal letter cookie cutters, and now she seems really excited that (with the stencil!) she can do it 'myself!'. I do have to secure the stencil to the page for her quite forcefully
One thing I tried that was a disaster! Maybe some kids have a light touch, but we bought a Crayola Studios Stylus for use with the IPad for her to write and draw!
That lasted all of five minutes or the next expense was going to be a new IPad! I think she thought she had to force the stylus through the IPad itself?...hhmm. Maybe in about 10 years. The one we found was recommended for three and up, but...maybe with a feather!