On the board draw three lines for writing on - the bottom line brown (the dirt), the middle line green (grass) and the top line blue (sky). Then when demonstrating how to draw a letter you can refer to the lines the letters touch and it keeps their attention easier than boring normal lines. This is just one of a number of more creative handwriting lessons I've used that are listed on my own teaching site, if you want to see some more (I've just picked one to post here).