A few follow-up thoughts from my last post on writing book reviews:
1) By no means do you have to have any unique skills or abilities to write a book review. You only need to be able to read--and the fact that you're here indicates this isn't a barrier for you.
2) Feel free to start informally. One idea: after the next book you read, write up a few thoughts, post them on Amazon.com and see what you learn from the process. There's no need to make this into an intense, time-consuming exercise.
3) Eventually, I'd recommend setting up your own book review blog. I have my own, which I've creatively named What I Just Read. You can set something up on Blogger in a few minutes.
4) It can also be an income source. Include affiliate links from Amazon to the books you discuss, and you'll provide an extra convenience to readers who may want to make a purchase. In return you'll get a few percentage points of the revenue from any sale.
5) Finally, you may even attract an audience of readers who share your interests and can recommend still more books to you.