A few things:
Using a project management solution even for simple jobs. I use Freedcamp, and it's great for single developers and teams.
Planning code in comments first. This has saved so much time. I might start a password reset script like:
// get $_POST data
// trim posts and validate
// connect to db
// search username / email combo
// good? -> add random hash to update_hash field -> send link with hash to email
// bad? -> throw error
It might change while I'm writing it, but it helps streamline my efforts.
Also, use something like gistbox to save your code snippets to have access to them from any chrome browser anywhere.
The Emmet code expansion plugin for coda 2 (works with sublime text and others too) has sped up my basic page building. Instead of having to type out <h1 class="entry-title"></h1> I can type h1.entry-title and press tab to have it expand to the full text. This seems trivial, but saves so much time once you get used to it. Here's the cheat sheet for the shortcuts.