Look in Google Play for themes. There are a lot of them, so choose a few dozen free ones that you like, download them and try them. Then uninstall all the ones you aren't going to use to free up all that space they're taking. You can use different launchers to give the phone different look - 360 Launcher, ADW.Launcher, Apex Launcher, GO Launcher EX, Next Launcher 3D Shell, Nova Launcher - there are a lot of different looking ones.