Bottom line: When seeking a guide to help you improve . . .
Do your homework. It is, after all, your Golf Stroke.
Demand excellence. Especially as evidenced by long-term student results verified by their direct testimonials.
Accept only excellence. Especially at the level to which you aspire. You will invest much time and money in the exercise. Rid yourself of the nagging worry, "If I 'bust my butt', will this work?"
Look for the right 'fit'. Psychological needs must be accommodated. Make sure you and your teacher 'mesh'. Life is way too short to endure personality conflicts, especially in relationships as close as this.