Doing a website review
You do not have to be an expert or professional webmaster to give a quality review. Website reviews from a novice can be just as important and beneficial as a website review from an expert/professional.

First Impression
Upon your initial visit to the website you are reviewing, use your first reaction to the website as a starting point for your review. Then continue by pretending this website offers what you might have been looking for had you done a search and found the website.

The good and the bad
Now all of us likes to hear that we have done good things so don't limit yourself to just looking for the bad things. Bring up the good things as well. The best reviews are those that cover the good and the bad.

Be honest, be direct and offer advice.
Don't buttercup your thoughts by posting what you think the person wants to hear. If you find the website lacks in visual appeal then mention this and offer some advice on how they can (in your personal opinion) improve the visual appeal.

A few points to look at
Is the purpose of the website clear?
How easy is it to navigate?
Do all functions appear to function properly?
Is the spelling and grammar correct?
Does the color theme and design work for the website?

As you can see, doing a simple quality website review is fairly simple. Don't feel intimidated because you are a novice.