Most of you are correct in that "advice" is generally not beneficial. I'd like to add that often those lessons for which you are paying money are not all that wonderful either. But, here are a few suggestions so that you do not miss hearing something important from someone.
1) Can that person tell you what is wrong in terms of the mistakes you are making with your body that prevents the horse from doing what it is supposed to do. Often, both the rider and the horse are crooked, and as long as the rider cannot correct her own position, there is no way to correctly change the horse's position.
2) Can that person explain to you the reason that you are riding a certain geometry? By riding a circle, for instance, what are you trying to develope in the horse. You need to identify what it is about the horse's position that needs to change, and with that change, you then correctly ride the circle. The circle is an ends, not a stand alone void. It is the demonstration of something important in the training. So too are all the movements.
3) After that person tells you what is wrong, can they then tell you how to make it correct within the training? This goes way beyond just prescribing an particular exercise to ride. It encompasses what changes need to happen within the exercise, how the change should feel, where does it fit in relationship to the skills needed for a particular level.
4)Does the person tell you whether you are ready to ride a particular level, and if not, why not. Too often I have seen riders attempting to ride levels(s) above the skill sets of both them and their horses.