Sublime Text is the editor of choice for many professional software developers because of its combination of power and simplicity. We used to recommend Emacs for Babel but, if you are a novice in these matters, we think it's better for you to use Sublime so you don't have to learn three things (Lisp, Babel and Emacs) at the same time. Emacs is a complex beast in itself and it takes years of practice to get used to it. Sublime will behave more like you expect from an editor.
If you have set up Babel through our new installation script, you probably already have Sublime installed and ready (if you don't, go for it!). If for some reason you prefer to do things manually, you can get Sublime from its webpage. We suggest then getting Package Control and using it to install the plugins rainbowth, SublimeREPL, Load File To REPL, BracketHighlighter and lispindent.
We have also specifically developed two plugins to make our life easier developing in Lisp: an improved Lisp package, and the theme Cool-Graal. git clone them into your Packages folder (~/.config/sublime-text-3/Packages in Linux, ~/Library/Application Support/Sublime Text 3/Packages in OSX). They will probably be useful for you too!
Anything you want to do with Sublime can be done with a menu option, so if you feel lost you just need to look through the menus. Nevertheless, there are some shortcuts that can speed up your development (note that some of them are set up by our installation script and may vary if you didn't make use of it):