Don’t have long tutorials at app launch explaining how to use the app. Instead you want to give your users tidbits of information as and when it’s needed. Make it contextual. Give tips and hints. Try to build design where the user figures out the app within a few seconds without needing an explicit tutorial. That’s where intuitive design principles come!
When something is so ingrained in mobile users’ minds such as pull to refresh, or pinch to zoom — stick to those rules for your app. And do NOT use those actions for some other goal. Like pull to add a new journal entry, it gets super confusing. A journal app I was using did that and it was confusing.
Don’t treat your users like idiot boxes. Don’t give a popup/alert to the user to confirm a frequent action. Ask for confirmation only for harmful actions users might regret — like deleting something, or making a purchase.
Unnecessary popups and alerts interrupt the flow and result in a bad user experience. Do not make your customers feel stupid.