If you stated to a provider that you were interested in hints at enhancing your prowess that many would give positive suggestions.

Make that part of your getting to know you conversation.

If you want to learn how to bake, don't ask the carpenter.  How do you know your skilz aren't fine now? How do you know the critique is a true critique on skills versus processing thru filters, which we all have?

Unless you are consistently hearing from several partners that they don't like a given thing you do, I would say you should ask what your  partner enjoys and try to work on that thing to please that given person. If she wants gentle caresses do that.  If she wants her head bouncing off the headboard, do that.  Best advice?  Be attentive in the moment and be flexible.

IMO my friend

When you make the date, mention that while you're as good as the next guy, you know that there are always areas for improvement. Pick a lady like Sinful Sinthia who is well reviewed and, through her posts, is always willing to help bring along newbies. Without making it seem too clinical, ask if the lady would participate in a few sessions including constructive criticism. Be up front about your wants and desires.

As long as you're RS2K or P411, you shouldn't have much trouble connecting with a "teacher."

Hurting someone's feeling is not constructive.  Helping them learn is a more positive experience for everyone.  That is if the gent is open to learning.

Negative reinforcement is counter-productive!