I have watched easily more than over 100 introduction videos, and it's getting easier and easier to find the right teacher from reviewing them. But what are some of the reasons you would use to try a teacher out?
For me it is mainly:
* A clear speaker. I can speak some Intermediate Spanish, but when the teacher mumbles, talks too softly, talks too quickly, seems disinterested, or just sounds like they're "rambling", I move onto the next one
* Noisy background music. Music is a wonderful way to present an introduction video but sometimes, it's so loud, I can't hear the speaker!
* A noisy background. One video I saw looked great as it was outdoors but unfortunately, all I could hear was a dog barking!
* A teacher or tutor not outlining their lesson plans or ideas. Sometimes I feel like I'm watching a TV show because the teacher is showing themselves bungee jumping or whatever, but I just want to know how they're going to teach!
* Enthusiasm and an interest in teaching is so important! Some videos are so boring in their plan discussion that I lose interest straight away
* A sense of humor and a happy personality are also great too, and are easy to see in the introduction video
Can anyone else provide some ideas that help them choose?
I think it's more about feeling and making a 'click' with the teacher. Besides matching time-zone and interests.
I think it also depends on the language level. For example, beginner students might focus on a good teaching technique and probably a totally planned program? An advanced student, on the other hand, might prefer an empathetic, easy and friendly-to-talk-with teacher.
Here my humble opinion, hope it helps.