There are two apps available in the Apple Store that'll do the work for you of creating a nice-looking icon on your springboard. They are Touch Icon Creator and Iconizer (both $.99 USD).
They both help you create icons for e-mail and URLs, while Iconizer will also allow you to set up a short cut/bookmark to make Facetime calls or Skype calls/chats. Note that I've not tried the latter two.
You find a picture of your choice (I usually use the logo of the web site ... or a picture of someone whose e-mail I'm setting up) - save it to your [default] Photo app. Then, launch either icon and walk through the steps and ta da! Nice icons on the desktop.
I've used both and they work great. Of course, and as always, YMMV.
Marilyn