I know I can use objects and walls but something much better and more efficient
Since I hear most (if not all) of the best memory athletes are using the method of loci/memory palaces in the same way as most books and the Art of Memory wiki describe, I doubt there is a much better way, at least for the tasks they have to do.
Why are you searching for something “better”? And for what kind of thing to memorize? Just asking for a better technique is like asking who the best singer is, there are a trillion different opinions there if you ask the question that vaguely.