Seminars are one of the best ways for someone to pick up new knowledge in jiu-jitsu. Every instructor has a different style, and while the basics of jiu-jitsu pertain to everyone (regardless of body type), the fancy and more specialized moves for your body type are sometimes harder to find and properly train. The best thing to do is to go to seminars with professors that have a similar body type to you and are famous for techniques that you can already do on a basic level. If you end up going to a seminar with them, you will hopefully be able to learn the details of the technique that you have been missing. Seminars are meant to be supplementary; they are the icing on the cake, and not the cake itself.
This is why traveling is such an important part of jiu-jitsu. BJJ is a deep and diverse sport in which you will never stop learning. The secret is not to know and master every single move, but to know all the basics and then layer them with some trickery of your own. Almost every jiu-jitsu master has their own specialty that they have developed since early belt levels. Sometimes you have to seek out that specific instructor to really pick their mind and gain that knowledge. For example, if you’re a De La Riva user, and you highly depend on that position, first priority should be to seek out a Ricardo De La Riva seminar. Considering that he originally developed the position and has been using it for decades, it puts him levels above the competitors that use the De La Riva guard today. Also, don’t forget that guys like De La Riva have decades of teaching experience and will be able to communicate the techniques in the best way possible.
The biggest complaint you will hear after a seminar is that the professor didn’t show anything “special” or it was “too basic.” It’s true that sometimes professors don’t want to share their top stuff at seminars to people that are not part of their own academy. In the majority of cases, the only people that will say the seminar wasn’t “‘special” or was “too basic” will be those who are not experienced enough to see the finer details of a position.
Find seminars with people that match your style. Make sure that when you are at the seminar, you really pay attention to the particular details of a position – you should hopefully find new aspects you didn’t know. You’d be surprised at how many black belts attend seminars and still come out with their eyes opened.