I would really recommend Handwriting without tears. My little one was in a full on Montessori for 2 years and ended up with horrid handwriting. He doesn't have any fine motor issues. I bought it and had him do 2 volumes during first grade, one page a day. They also do some handwriting in first and second grade (I switched him to our public school).
Now in second grade, his handwriting is pretty good! It isn't the best, but it's probably average to above average. Good enough! Just buy it on amazon.com, not very expensive.
If you long-term your child has horrid handwriting forever, it can affect- how they do on the SAT writing part of the test; affect how fast and well they can take notes in school, etc.