Photocopy sheets that demonstrate different letter joins back-to-back. Laminate the sheets so that children can write on them with a non-permanent marker. When they are happy with their attempts they can try writing them into their books.
My special day
To raise a child's self-esteem try "My Special Day". Each child gets a special day where they can ask for two different rounds of applause, wear a badge that says "Special Day" and choose any end-of-day activities or games, if appropriate. Each child also gets a piece of paper that every member of the class has signed saying why that child is special, such as "I like Amy because she is always kind and caring...." The children love it.
A brief note
If I want to leave a message in a child's exercise book, I use a sticky note. This is particularly useful for less complimentary remarks. I also use small cut-up pieces of sticky notes to mark where a child has to finish work, answer a question, and so on. The brightly coloured paper sticking out of the book serves as a reminder that something has to be done. For the less able, it is useful to leave a note about exactly what needs to be written, such as a missing title. A note on the front of a book reminds me to speak to a child before they start their next piece of work.