I suffered from foggy glasses a lot, I prefer to wear clear lenses since I tend to ride after dark frequently. I tried a few of different cycling glasses with clear lenses, eyeglasses with anti-fog coating, motorcycle goggles, and several pairs of safety glasses with no luck.
I finally found a pair of $9 MSA Safety Works safety goggles with anti fog coating that work well, don't fog easily, and have good peripheral coverage without obscuring my vision. They sit far enough off my face that they prevent fog when I'm stopped. So far this has been the best alternative to bulky ski goggles that I've used.
One of the biggest things you can do for any glasses to prevent fog is to keep them clean and free of sweat, oil, and residue. I don't know if this is the best method, but i tend to just clean my glasses with a touch of dish soap and rinse well. Don't use harsh cleaners like windex or alcohol which may strip the anti-scratch and anti-fog coatings.
Also, do your best to avoid scratching your glasses, as this will make it harder to see and often can causes refraction when looking at light sources. I keep a glasses case in my bag for storage when not in use.