Review writing as a very particular style of writing, it uses narrative writing, research, and opinion all in one go. It can also be tricky when you start out to think about enough things to talk about, and there's always that question of ‘who is going to want to read this?’ The answer is to choose the right products or places to review. You will always find that there are like-minded people out there, and people who want to know your honest opinion.
