S.B.
Last year in kindergarten, our son had the worst handwriting in the class. We (and the teacher) struggled to read almost anything he wrote. At the beginning of the year, his teacher told us to give things some time. By the end of the year, she was also concerned.
His teacher gave us some ideas to use over the summer. She said if we didn't see improvement in first grade, then testing may be an option. First, he had to continue writing and journaling. We didn't want this to be too much "work". We didn't want to make it a fight or make him hate writing. So we worked out a system. For every page he wrote he would get a poker chip. The poker chips could be cashed in for screen time. It motivated him to do it. We never had to ask him, it was always his idea. And since we let him write about anything he wanted, he enjoyed making up stories when he was bored. We would use his stories to casually talk about sentence structure or punctuation. We tred lightly. We wanted to teach without putting him off.
Then she said we needed to help him with fine motor skills and hand strength. So we played with a lot of playdough. We made games where he had to move and transport small object using tweezers or clothes pins (he really loved these games). We did lots of cutting and hole punch activities. And we left stress balls lying around to play with. We also made paper airplanes and encouraged playing with legos. And we taught him to do some simple embroidery. I really think this helped him immensely and he really loves to sew now.
We NEVER called it handwriting work. We never forced it. They were just fun silly things we planned for him to do. We did see improvement over the summer, but we knew he had a long way to go.
When first grade started, we talked with his teacher about our concerns immediately. She assured us that we would see improvement, because kids gain so much in the area of confidence and fine motor coordination in first grade. And sure enough, slowly we saw the handwriting get better. He is not the best writer in the class, but you can read everything he writes this year and he is definitely no longer the worst writer in the class!! It has been quite amazing to see his work transform.