We know we've found a good teacher for us when they role model, or speak to, an aspect of who or how we want to be.
There is always something trying to wake up within us. We are often just about to know what it is. So, when a teacher touches on what we are ready to learn then they truly have our attention. There is a flash of recognition, importance and opportunity. Maybe they just clarified a pattern you've been puzzling over or they said the perfect words to describe a feeling you can't articulate. When that happens you hear your inner voice saying "yes" and "more." There is both a level of familiarity and a lot of new territory to explore. And you want to explore it - which is all it takes to be a great student. It's not that you're looking to follow a guru, it's that you're both tuned into the same big idea. How you understand or experience it is similar enough to allow you to communicate about it.
It doesn't matter if great teachers give you homework because the teachings will stay with you, constantly unfolding. There are many teachers, so having options isn't the problem. Find the ones who resonate with you.