1. Use Spotlight to navigate your Mac. This means you can hide the dock when not in use (under Dock Preferences). This gives you more screen space to work with. Navigating with the Spotlight shortcuts also will quicken speed over time.
Spotlight = cmd + spacebar
2. Multiple Desktops
The 13" screen can be quite limiting when you are coding. If you don't want to splash out on a second monitor then you can use the multiple desktop functionality that Mac OS has. Click the F3 button on your keyboard and you should get this:
Now simply drag your application into the second desktop. The best way to navigate is by using four finger swipe on the trackpad or alternatively you can press ctrl + left arrow or ctrl + right arrow.
Open new tab = cmd + t
Highlight the URL = cmd + l
4. Sublime Text for Mac
Delete line = cmd + backspace