Awesome

ColorSchemeEditor

Real-time color scheme editor plugin for Sublime Text 2/3.

Real-time scope display

Activate the color scheme you want to edit. it must be an editable file on your disk, not inside a .sublime-package. If you are using Sublime Text 3 and your theme is inside a package, install the PackageResourceViewer plugin, open the Command Palette, type prv, and select PackageResourceViewer: Open Resource. Scroll down until you find the name of the package you want (the built-in color schemes are in Color Scheme - Default) and hit Enter. You can now find the .tmTheme file you want and hit Enter. The interface allows you to select more files, just hit Escape when you're done. Now, finally, you need to select File -> Save for each file you extracted, or it won't show up in your Packages folder (Preferences -> Browse Packages...). Once you're done, you can close the .tmTheme file tabs.
Open some code and press Shift+F12.
Your color scheme should open in a separate pane.
As you put the cursor on different source elements, the other pane will find and display the XML element that is affecting this element.
If more than one style element affects the code element, the most relevant style match is displayed first. You can go to the other matches with Ctrl+Alt+Right and Ctrl+Alt+Left.
Change the styles as you wish and save so Sublime Text will reload the styles and display your changes.
When you are done editing press Shift+F12 again or close the view of the color scheme file.

Borislav Peev (borislav.asdf at gmail dot com)