Yeah good question, are you simply talking about bridle path etc or a full body clip?
Google is the answer.. be cautious of small nicks etc, and be sure to brush or preferably hose the horse off after being clipped, so that any small hairs that have lodged into tiny nicks can be removed. If they stay in there they can cause small swellings and get infected.
Also tip to give pony a baby oil bath after you have clipped him, and don't hose off the baby oil just rug up in an old rug so all dirt comes to the surface of the ponies' hair, cleaning him up real good and giving him a lovely shine after you have brushed him. :)