I'm just looking into creating apps and this is good advice. I'd like to add from the customer perspective that adding in freebies is a good idea (I use 37 Signals backpackit for work, but love it as I can also sign up for free for my personal use). Another good idea is having someone answer customer service questions promptly. Having a FAQ people can search themselves is OK, but I love when I can type in a question and just get an answer right way via an email. There is a very low cost software out there to do this called sufaq.com. I'd be really interested to see what else is out there free or low cost to handle back end issues that come up with the app making/promoting process. __