My best entrepreneurial advice is to start.
Products should speak for themselves, and marketing should support that.
I have two iPhones, one for day and one for the night.
There are a lot of things that are uncomfortable and hard to do, and the longer you put off those things, the harder they get.
If I learned one thing working at Facebook: If users are trying to use your app in a certain way, get out of their way and let them.
Simple and intuitive design is what inspires and drives me.