How do I make icons larger on my iPad?

If you mean the homescreen icons then you can't, they are a fixed size : http://www.apple.com/feedback/ipad.html

The only thing that will increase the icons size is the 'zoom' feature (Settings > General > Accessibility > Zoom) but that zooms the whole homescreen meaning that icons will be off the side or top/bottom of the screen and you have to scroll the iPad's screen in order to view them - which I assume that you don't want to happen.