Very useful video tutorial, but someone suggested in that thread to visit videogoogle or youtube for more tuts.. Im advising you not to..
http://video.google.co.uk/videoplay?docid=7146981249758818663&q=pixel+tutorial I really want to meet this kid, it took him half an hour to make this.. I know he may just be a beginner but that doesn't explain why he released a tutorial on the web..
Andy you're on the right tracks but don't think of the tiles as patterns, think of them as dirt.. you have to make it look like dirt at the moment it just like this pattern repeated again and again.
Make sure it doesn't look like a pattern because in a game, yes it's too repetitive, it needs to look like
dirt.. Maybe it'd help to have some references.. Funnily enough I found the perfect few to help..
Maybe having a 3rd colour may help? And brighten up the colours.. It may look too busy at 100% but this would probably be best played at like 200%. Just a suggestion