I'm a rookie exterminator. What am I doing wrong?

I'm a rookie exterminator out of New England. I've been doing this for about three months now so I'm really new and still learning. I'm finding that these little critters are extremely difficult to kill out of wood houses. I work for a medium-sized pest control company (about 20 technicians) and I'm wanting to know what I can do better. I'm just seeking some advice from anyone with experience who can enlighten me as to what I'm doing wrong. Here are my procedures: <br><br>(1) Once I find a crack with them in it, I inject the crack with a mixture of a non-repellent insecticide and Gentrol IGR. If the crack is deep enough, I give the crack a "swipe" of the bottle to be sure I'm getting some of the chemical onto the outside of the crack/sill. <br><br>(2) If the crack is deep enough to get a full "swipe", I then seal the crack with caulk. If I have to drill into the crack, I'll plug the hole with a plug. <br><br>(3) I will also spray the foundation with a pyrethrin and Gentrol IGR mixture, as well as a pyrethrin combined with a combi-product that includes hydramethylnon. <br><br>I'm just wondering how to improve my work efficiency to get rid of these critters quicker and more efficiently. What do you do to get rid of them efficiently? Any advice would be greatly appreciated. Thanks.