I catch a couple of swarms in traps each year. Not great as I have about 15 traps out. I am lazy and leave them out all year and just throw a little lemon grass oil in them each march along the line as jim said, qtip in baggy. I use one deep and as jim said, use foundationless frames. If I have a frame of dark brood comb, I might throw that in also and it probably helps but like I said, I am usually too lazy to do so. I put some of them at my family's houses and ask them to call me if they see bees messing with the entrance. I find bees don't care about the traps unless they are looking for a home and so if a bee is seen to be interested and I get call, odds are pretty good. I keep a trap in my back yard that I can see regularly and it helps me as when I see a bee messing with it, I know it is a good time to go look at my hives and look at the trees around them incase one of my hives has swarmed. Most times if a hive does swarm, they will not go far and will be in a tree close to the hives and you can just shake them into a box. I have saved several of mine this way. Good luck.
I also agree with putting the traps low enough to reach them from the ground easily. It just is not worth doing more and higher is just too much of a hassle. I make little platforms that I slide the deep on and that way when I catch one I can just take another trap with me and when I pick the bees up, put a new trap back. This cuts down on trips to and from.
