Reviews are fairly simple as long as you describe it in full detail, use many descriptive words (adjectives), and give specific examples. For example, if you were to write a review on McDonalds, one might say this:
McDonalds is a great place to eat if you are in a hurry and not looking to spend a lot of money. On my recent visit, there was a long line at the counter. That said, the cashier was efficient and moved the customers through quickly. Plus, you can feed an entire family of five for under $30. That is really good for people on a budget. Overall, the restaurant was clean and located conveniently to hotels in the area.