Maintenance
This post was originally on a blog I started for creating web applications. This post goes into maintenance of web applications.
Setup an Error/Bug Reporting Solution
Use Github's issue tracker, or JIRA, or anything. Keeping track of issues, enhancements, and bugs in progress helps tremendously down the line.
Setup a Contact Form
Simple email forms or using other services like Reddit or even forums can help users give you suggestions and criticism.
Documentation
Document how the application works, the deployment progress, and anything else you can! Those who do future maintenance will thank you.
Backup/Restore Strategy
Have a backup strategy and a restore strategy.
Version Control Your Project
Use Subversion, Mecurial, Git to version control your files. Preferably Git ;) .
Setup Unit Tests/Acceptance Tests/Regression Test etc
Getting any type of tests is very useful, especially acceptance testing and integration testing.
Setup Logging
Log any application errors, user errors, exceptions, etc.