Lets give this a go. You stand on 1 leg (do both sides so you can compare) you squat in case of weakness of minor muscles you will have trouble to control the movement. The hip should stay aligned with the knee and the knee aligned with the foot ( hip- mid knee cap vertical line pointing in between big and 2nd toe) If the knee points inwards or outwards (when you try to control) you will have weaknesses (mainly Gluts). If you see that your pelvis drops or rotates you have weaknesses (your body just attempts to hide weaknesses) (these are mainly core stability weaknesses).
You could try with a book from Joanna Elphinston about gymball exercises which works mainly on coordination and what I have seen is easy to understand because it is filled with pictures what is correct and incorrect and this may help you to solve your problem. Having said this: If you have not seen your Gp (imaging) or tried a Physiotherapist (best one who has worked or is working within sports to have a look you are taking some chance to get it all wrong.