In the realm of BDSM (and, quite frankly, the majority of the mundane world), being "good" at anything is hugely subjective..

I am going to assume your Master is male and you are female? It does not matter, but you should offer a little more in the manner of specifics.. Are you looking to be publicly humiliated, or just trolling for quick masturbation material?

In any event, it would be in your Master's best interest to teach you how his "good" submissives should/n't exist, in and out of his presence..

I am always happy to share my perspective and singular understanding on the realm of power exchange..