Another bit of the "Shoot from a low angle" trick is to use a wider lens. The wider the lens, the closer you can get to the ground and to the subject (i.e. you!) and the more exaggerated the effect will be. You can go from mild to totally crazy with a fisheye or an ultrawide. Here's
a somewhat outlandish example I took with a 10mm lens. I was experimenting so it's not a very flattering shot, but you get the idea.