Thanks! Longer may come down the road but some off the top of my head:

Mobile is totally different from web - small screen, on the go, harder to easily iterate after launch

Get a feel for the apps you like/aspire to be - check out cool apps and get ideas from the ones you like

Figure out what you're optimizing for - limited real estate means you need to focus on the flows that matter to you

Do multiple rounds of user testing - you are going to be surprised by what people try to do

Polish comes at the very end - easy to get ahead of yourself and you might have to throw it out