Learning how to print letters is not something that children WANT to learn by sitting at the table and doing worksheets. Worksheets are NOT for preschoolers, toddlers or ANY age for that matter. I don't like worksheets.
That being said, every once in a while my daughter wants to do her worksheets. She has a workbook suitable to her age - not harder - and she does it by herself. If she needs help reading instructions, I will help. But I don't even go near the kitchen when she's doing them because I want it to be fun for her and I'm scared that if I sit there, looking over her shoulder she will no longer enjoy them.
But I did want to practice letter making with her because she would be starting Kindergarten (we did this activity back in the summer, now she's a full grown Kindergarten girl). So we found some lined paper, a pencil and we sat down to write a letter. She wanted to write to her grandparents. She told me what she wanted to say and I read out the letters that she needed to make. I did it this way instead of writing so that she would have to make the letters by memory, not by copying what mommy made on the other piece of paper.
Once the letter was written there was even more learning! She learned where to put the stamp and the address of both of the people on the envelope. Then she folded up her letter and we walked down to the mailbox. About three days later when checking for mail she was amazed to get back a letter from her grandparents! It was wonderful to see her eyes light up! "It's for me!"