When looking for drum teachers, ask around before deciding. If you have friends that have taken, or are taking beginner drum lessons, ask them first.
And if friends do have a teacher also see if they are enjoying the classes. Although this is a learning experience, you still want to have a good time in the process.
If you are interested in online drum classes make sure that they are simple enough for you to follow along. There is no point in taking a class that leaves you confused at the end of the day.
The most important thing to remember if you are taking classes of any type of to make sure you are matched to the teacher. This means that you are able to learn from the style of a specific teacher.
Whether online or not, the way a person teaches has a lot to do with your ability to absorb the lesson. If you are a hands on person, then you will not do as well with drum teachers that use mostly written materials in the class. Checking with a few of the students who have already taken a class is also very helpful. That will give you an idea of how well the teacher is perceived by their students.