Koji had no desire nor drive to play tug. Oh, he'd drive for food, but not much else (including DH). However, like many of you, I was instructed to build drive with a toy. Well, it's been how long that I've been training? 2 years? And well, although he tugs a LOT better now, he's still not big on toys. He's just not a toy dog. Heck, Miko is a better tugger than Koji and loves it more.
So, instead of tugging, what we do with the toy is fill it with food (it's also a bait bag), we put it on the ground, let him drive to it. He just sniffs it nothing more. So my job was to move it around to get him to want it. He may tug, but just going after it was good enough and you open it up and treat him.
I also tend to use it to throw. Let him know treats are in it, and toss it when needed. Trust me, I don't use it at trials because he's just not interested in it. I bought him one of those snakes in a box (actually it's food/carrots in a big carrot) and he could careless. He'll only pull them out to eat the strings off of them (sigh).
Does he have more drive since we've learned to tug? Yes. But is his drive even stronger knowing he has food at the end? Yes. So, I use tug then give him what he really wants. Food. Because if I use ONLY tug.....he gets disappointed and his willingness/drive goes WAY down and FAST!
This is my 2 cents for what worked and didn't work for me. Strangely enough, he loves to tug on his leash, but it's typically only when he's playing, NOT when he's working.