For me I use this exercise for first aid.
Here is what I use when my head gets over crammed with thoughts. Breathe in a natural way. Silently count one on the inhale and 2 on the exhale. 3 on the inhale and 4 on the exhale. Continue up to 10 then go back to 1. This helps me focus on breathing rather than the wall of thoughts.

Psych Central has forums
OCD and Trichotillomania - Forums at Psych Central

Also other resources.
http://en.wikipedia.org/wiki/Excoriation_disorder