4. Persistence Pays Off
App review sites are inundated with review requests. Some sites know that you are eager to get a review and solicit your business by charging for reviews. It's your call whether to use these services. I'm not necessarily against them if the site has the traffic to back up its fees.
Do your homework, though, before spending lots of money on review sites that don't generate a lot of traffic.
For regular nonpaying reviews, you'll need to be persistent. If after submitting your app for a review you don't hear back in 10 days, send an email to the reviewer (if you have the email address) or to the editor. Ask them again to take a look at your app and briefly explain why they should look at your app. Give them a compelling reason to look at your app now.
If you are currently being included in the "What's Hot" or "New and Noteworthy" categories of the App Store, be sure to mention this to the reviewer. They love to write about what's currently hot in the market. Don't miss your chance to tout the recent notoriety of your app.