How to promote iOS app?
Tutorials iOS iPhone iPadsubmit your app for review on websites
Add your app as an alternative
alternativeto.net is a website to list apps and software tools and their alternatives. Submit your app as an alternative to some categories of apps or a specific app.
Announce that your app is alive and they can use it for blah blah blah. Post to threads that are probably want your app functionality.
Tell people on Facebook about your app. Post on groups that are interested in your app features.
Tweet that you launched an app. And explain the app purpose and functionalities and features in some tweets.
Tell your connections about your app. Tell a story of developing your app. Invite them to try your app.
advertising
Make an ad campaign on the store or Google search to attract interested people to use your app.
Create website
Create website and landing page for your app.
Content marketing
Write content such as articles and blog posts to explain how to use your app in different scenarios.