The last step is to make sure they offer some sort of an uptime guarantee. Some companies offer a 99% uptime guarantee, and if your site is not up that much, you get the month free. While this does not bring you back the potential clients that you have lost, it does encourage hosts to have their servers up as much as possible.
Be careful not to be ripped off though. While I am telling you not to spend too little, you have to be careful not to spend too much. If you are interested in a host and you feel they might be trying to charge you a little too much, feel free to contact me and I'll check them out for you.