First you need decent software, if you have Photoshop you should be good, if not download this program http://www.gimp.org/
, it's a free Photoshop pretty much. Then you'll need fonts, brushes, and renders (AKA, resources) to use. As for the brushes and even a tutorial go to, http://www.deviantart.com/
. As for fonts, http://www.dafonts.com/
, for renders use http://www.planetrenders.net
. You can C4Ds from PlanetRenders and DeviantArt. At DeviantArt, search for a tutorial, you'll need it. If you do use GIMP go to www.gimptalk.com
for a bunch of good tutorials. Hope that helped. If you need more, I can give you a few GIMP tips.