Performance testing of a sitecore website

My client gave me a Sitecore website to do some performance testing.I really don't have any expirence with Sitecore website or Sitecore itself (which I am working on now).I have some idea of performance testing of a website and also got additional info from stackflow. But I am curious to know if there is any difference in testing a sitecore website? What is the best practice to test a Sitecore website? Little bit about the performance testing scope:

1. The website handles different kind of enrollment path for students. So there are a couple of enrollment paths , all of which ends with a payment done by the customer.There can be more than 1 student enrolling at a time (like 6 together). Performance testing will include enrollments for all of these paths.
2. A lot of customers trying to enroll at the same time in the same enrollment path and different enrollment paths.
3. Also have to keep in mind that since this is a customer facing website the images/texts/files that are hosted in Sitecore should be shown in the website quite quickly.

Any help is appreciated.Thanks!