A great pre-writing activity that has your child form letters with her finger.
-Another great multisensory exercise is to have your preschooler form lather and shaving cream. You can use a cookie sheet as your surface. Using my pointer finger, I form a letter cream. For example, if want to teach letter M, I'll say start at the top, big line down, read it, jump to the top big line slides down, big line goes up. Have your child chase over the letter you just formed then have her spread shaving cream all over the cookie sheet again and form the letter independently.