Before you publish . . .
You'd think the most frustrating part of finding good books to review would be the suffering: the traversing of absolutely horrible writing. Not so. Those texts are easy to toss aside [delete]. The painful ones are the books that are almost there, the ones that not only would be great books, but would probably find their way to a commercial publisher.
So here's what I suggest you do: Join a writing group. Regardless of what you may think, your writing is not better than the other hacks there (I was part of one for years). And take a look at how many commercially published authors thank the folks in their writing groups in their acknowledgements sections. They work--if you can take criticism.
And if you can't? Man, you are in the wrong industry.
Your book, from the first time it is released (into the wild) is being critiqued. Agents, editors, book reviewers, amateur book reviews (read: Amazon), and so on.
There are a lot of things you can do to improve your novel or memoir (like hiring an outside editor) but nothing does the trick (and costs nothing) like a writing group. If you hire an editor, she may tell you to change the way a character speaks or to delete a scene or whatever. But with a writing group you get to listen to other people discuss your book, where one person may want to see a change but another may totally disagree.
Or the entire group may be telling you the same thing--in which case, that thing needs to be fixed.
Having a finished manuscript on your hard drive is not enough. I know it seems exciting to imagine it could be in the marketplace in a few months (supposedly) but if you take the time to get involved in a writing group, it can make the difference between an Authorhouse logo and a William Morrow logo on the spine.