Dress warmly. It's easy to get cold when you're inactive... and unless you live far to the south, it will get chilly. In many locations, it's even advisable to crawl inside a sleeping bag.
Turn off all lights, or if necessary, travel to a dark location. Light pollution can seriously impact your viewing activities.
Use a reclining chair or hammock. Since the event will take place overhead, you’ll want to relieve neck strain by lying on your back.
Find a location with a good unobstructed view. Meteors appear to emanate from the radiant, but.. they can show up anywhere in the sky. Also
Keep a count. Set a timer to go off every 10 minutes or so. You can then use this to gauge the rate at which meteors are being observed.

The accompanying image shows a Perseid Fireball and was taken by S. Kohle & B. Koch