Now that Little-N is reading, he suddenly decided that he can write. It's important that children are taught to write with the correct letter formation. Luckily the Montessori materials already start them off with the correct movements but you do have to go a step further. What I have been doing for the last few years is teaching children to write using the letter families, starting with C then O then a and slowly moving on once each letter has been mastered.
I start my lesson by asking if s/he child would like to see how I write my letter [naming one that s/he wrote]. I then write the letter on a piece of paper and ask the child if they would like to practice writing the letter with me. If the answer is yes then I guide the child to get the sandpaper letter, we feel it as many times as the child wants and then I ask them to try and write it on paper [or on the sand tray or black board]. Usually that's all I need to do, I then get up and leave the child to practice. If i see the child struggling I will ask him/her to feel the sandpaper letter again and usually they succeed.
Sometimes I do get a few children who are getting older and are unable to write alone. If I see that they are frustrated as they want to write but can't, that is when I do get out the dotted writing. I found that the guidance of dotted letters help give the child a boost as well as making it an easier task.
Little-N saw older children writing on these sheets, he tried them and enjoyed himself. Sometimes [like this morning] I would give him a sheet to work on while I work on my assignments for my course.
Always remember that the important thing about teaching a child to write is that they enjoy it! If they do they will always love writing.