When One was beginning 1st grade - 3 1/2 years ago - we were told by his teacher and the lower school principal that "unless we did something about his horrible handwriting, he would fall farther and farther behind his classmates." We were a little confused at the time; he was six, he was a boy, and we didn't think six year old boys were known for their handwriting. But, apparently, it was a major problem for these two women, and he was threatened with falling behind in a class that was already far too easy for him in terms of learning materials. No flexibility was suggested at all; instead what they offered was punitive more than anything else.
What did we do? Well, this was maybe the 5th most important problem we had with the school, so we did what most parents who have already paid way too much in tuition would do: we pulled him out of the school. I home-schooled him that year, and we didn't worry too much about his fine motor skills, at least not while doing school work. I would fill in the addition and subtraction problems that he could do in his head, he would narrate book reports to me while I typed on the laptop, and we did spelling verbally as well. It was a short-term fix, but we didn't want him to miss out on learning because his hands weren't ready to catch up with his brain. In his free time, he participated in sports that involved hand/eye coordination and hand strength: baseball and fencing. He didn't notice that this was helping, but it was.
The next two years? That's when we worked on his motor skills at school as well - it was time for it at that point. He learned cursive in Montessori, and suddenly his handwriting was completely legible. He did a lot of art in Montessori as well, and doing an enjoyable task with his hands - everything from drawing to painting to weaving - was a painless way to build motor skills. He also began to take after school art classes, something that continues to this day. Taekwondo helped his upper body and arm strength, which in turn has helped him write and draw for longer periods of time without tiring.
None of this was really planned by Husband and me, but it has worked wonderfully in helping One to "catch up" on his fine motor skills. Not that I ever really felt there was catching up to do; some skills develop before others, and this was what lagged behind for him. What solved the problem was time, encouragement, and an enjoyable way to work on the skills he lacked. He didn't need us to have a complete parent freak-out when he couldn't print perfectly at 6; he just needed us to keep an eye on things and look for ways to work on the problem whenever we could.
I write this because I know we're not the only parents who have had this message delivered to them. Sometimes it comes in a tone of "go fix this child so we may teach him properly" and sometimes it is delivered more compassionately. Regardless of how the message is conveyed, I would encourage you to trust your instincts as a parent and look for alternative solutions to the perceived problem. If what you've been told seems to you as non-sensical as a 6 year old boy with perfect penmanship seemed to me, do your homework: get some books from the library, read on the internet, talk to some friends with older children. In other words, educate yourself in order to test your initial instincts. If it seems like you may be right, then go with what works.
And while I know he's still no Rembrandt, here's what works for me: