You can easily tap a file name to open editing space. If you're editing a remote file you will be asked whether the fill be re-downloaded or not.
If you're editing a local file, iOS will automatically save the file everytime you make a change.
Distraction Free Editing
For better coding experience you can hide the top navigation bar and leave only the editor space. Simply pinch out over the editor area fo hide it.
Keyboard Shortcut
If you use external keyboard, use ⌘(Command) + . to finish editing, and the top toolbar will get back on editor area.
There some keyboard shortcuts which you can use while editing a file. For complete list of keyboard shortcuts, you can check in Settings - Editor - Keyboard Shortcuts
If you're working on a dropbox based html file, you probably will find that your html file preview is not properly displayed in the built-in previewer browser.
It's because your css file is served over relative path and dropbox doesn't support it.
But don't worry, there's a workaround for this.
You just need to preview your css file with the built-in browser then copy the url to your html file.
Don't forget to save the html file before previewing it.
Video : How to Make the previewer browser working properly with dropbox connection
Extra Keyboard is a shortkey collection to let you access frequently used brackets / characters during programming quickly. Swipe left or right over the light grey button to show different shortcuts.
You can alse create your own shortkey with cursor position support. Simply tap over the lightning icon then tap the (+) sign in the right section of extra key bar.