When you're in editing mode, and working with multiple layers, long-press over the area of the layer you want to edit. A pop-up comes up, which has "Edit" at the top and a number of different options. Toward the bottom, the layers under where you long-pressed will be listed. Just select the layer you want to edit, and the yellow box for that particular layer will show. Then you can long-press on that yellow box to edit that layer. Make sense?
By the way, what do you mean about "installing different fonts" -- if you're talking about your system font, I can walk you through how to do that (you can use Skaggz fontchanger for a simple method, but that didn't have the Zegoe/Zune font that I wanted, so I did it manually). If you're talking about the icon or label fonts, you can do that in the Edit function for the tray or springboard you're working with, in the Icon/Label style menu (you can also choose whether you want the icon labels to show at all, and how large you want your icons to be).
in one axis.
