They are pretty wary as you probably know, set up with a decoy of some kind to keep their attention. Understanding that they almost always come from downwind helps a lot, they also like to follow cover so along a fence line or bush works well. I start calling softly in case one is nearby and I slowly increase the volume, I usually call every few minutes but others like to call incessantly, I dunno which really works best though. Get a squeaker and if you see one switch to that, it seems to bring them in closer than a howling rabbit. If you can set up crosswind that's a good idea too and hopefully they won't scent you first. Don't walk downwind of your calling stand because if they hit your scent trail they will probably take off. Bows might work but so do other "tools" and if you are serious about getting lots it might bear thinking about. They will see the smallest movement and hear the smallest unnatural sound so keep it all to a minimum especially at bow range.