Teaching and assisting students with learning disabilities

Tools and techniques on how to deal with students in a classroom setting who have learning disabilities. This focuses primarily on helping students with OCD, otherwise known as obsessive compulsive disorder.  There are a few simple things that teachers who don't have experience can do to help the child feel confident and succeed.

There is a student with Obsessive Compulsive Disorder (OCD) and he/she is having problems in the classroom such as moving from one task to the next, excessive erasing of words on papers (so bad that it causes holes) and they need everything to be perfect. How would you help them adjust and fit in?