The majority of serious book reviewers do their reviews on a blog. Your blog can take various forms, whether you choose to self-host a Wordpress blog or you'd rather opt to put a blog on the Blogger platform, you have plenty of options for your setup. However, some reviewers enjoy the extra traffic boost that can be gained from using a platform such as Wizzley (where you're currently reading this article). One way or another, you're going to want to make sure that your review policy is prominently placed so that readers and authors can both find it without having to go on a hunt.
Wordpress and Blogger both allow you to create pages on your blog. Note that pages aren't the same thing as posts. Pages will remain "pinned" at the location where the pages widget has been installed. If you are using any kind of a book blog at all (even if all you use it for are the book blog memes, like I do), I recommend putting your review policy on one of these pages, then make sure that you have the pages widget installed. I like to have mine display at the top of the page, but you can also put them in the side column on either Blogger or Wordpress. In fact, you can do both. Either way, make sure that your review policy link is prominently displayed!
But what should you do if you're putting your book reviews on a platform such as Wizzley? If you do have a blog (like I do), I recommend using the "my website" space of your profile to include the link to your review policy on your blog. Most platforms have a space for you to include a link to your website. If your platform does not, then include it as a hyperlink in the profile text, where possible.
On the other hand, not everyone is going to run a book blog of some sort or another. If you only do book reviews very occasionally, then there really isn't any point in keeping a whole blog for the sole purpose of writing reviews. You might use another service for your book reviews, but you'll still want to have a review policy posted publicly. For this, you have two options.
The first option is to create a page for your review policy, then link to this as suggested above. I don't like this option, however, because the chances of the page getting any traffic, direct or indirect, is unlikely. Instead, I suggest using your profile's "about me" field to include your review policy there. You'd be surprised how many visitors will click through to your profile page to learn more about you, and this is a great way to earn yourself some advanced reader copies!