Doug, when you're without a dog, the key is to go everywhere a dog would! In other words, you gotta get in there in the thick stuff. You've got to kick or step on every good hiding spot, and the thicker the better. The only problem is you better be a
quick shot. When you're in the thick stuff, you usually can't see that far.
Most people have better luck kickin' up themselves in fencerows -- more so than on ditch dumps. On fencerows, once you get one up, you can see him run up or back a long ways usually.
Hope that helps. We raised beagles and I've probably taken a few thousand rabbits over my lifetime, and have hunted without dogs plenty of times too. It's how I survived in undergraduate school!