Choosing a Good Kung Fu Instructor

When I judge a Kung Fu tournament and see the students who do 'something' that isn't close to kung fu I wonder, "How did these people find their instructor? How did the instructor get there"?
Many Kung Fu instructors teach some blends of martial arts or just something that they made up after a few years of learning. It looks good but has no substance. How do you find out about the instructors background and ability? Is what they are teaching legitimate? Does it work?
There are certain things you should look into to determine the quality of an instructor or school.
Do your research- Look at what they say they are teaching. Is it "traditional" or "contemporary"? If it is traditional, there should be background on the style they teach. This will give you information as to whether the instructor is teaching the actual style. I have seen many teachers claiming that they teach Ying Jow Pai (Eagle Claw, the style that I teach) who don't even teach the basic concepts of the style, much less the traditional forms (if someone from NYC teaches Ying Jow and someone in Greece does, also, they should have common forms and, at least, common techniques and concepts). There will be a lineage. Are the instructors in the lineage legit?
If it is a "contemporary" style you have a harder time since there will not be as much "background to research. There might be information about the instructor- Did they learn any traditional styles? Did they compete in any major tournaments and perform well? Do the current students do well in tournaments? A Contemporary style might be something like a mixed martial art style or a 'personalized' name added to a 'Traditional" style name. When looking at one of these, know what YOU want to get out of your training; Fitness? Self-defense? Tournament fighting ability? There are some good "Contemporary" styles out there. Jeet Kune Do is a good example of a "Contemporary" style in that Bruce Lee created the concepts in the '70's. The principles work when put to use in fighting which is what the 'style' is supposed to be for. The problem with it nowadays is that there are many 'fraudulent' instructors out there who aren't teaching the legit system. They may have read Bruce Lee's book and applied it to what they had known prior.
Don't be fooled by 'demonstrations' that in instructor does with his students. Try a class. See how it feels for yourself. Use your common sense and intuition. If it doesn't feel right, don't! Do they press you to join?
A Martial Art should be something that teaches you the ART- Usually forms and there are certain things that are universal in forms; Stances (srong and balanced), focus, meaning
and FIGHTING- A system is only as good as the practitioner BUT there is one thing that holds true regardless- DOES the technique work when applied properly?
I hope this helps you in your search.