Champions constantly playtest, hours each day. When they can't playtest with each other, they play their own decks against each other. Lot of people want to be champions, but can't or won't put in the work. Once when I was between jobs, I won a regionals, then top 16nd in another one. I playtested a lot in those days. While working, I can't put in the time and I will never have the kind of time on my hands that I had as a teenager to do anything. Different priorities and I'm ok with that.
If you want to be the best, you've got to play the best. First, though, you've got to cultivate your own play level so that you have something to bring to the table. Build archetypes and play them against each other until you understand the strategy of each deck and you don't make misplays. Once you're there, then you should be able to gather enough associates to test against.
If you want to be the best, you've got to play the best. First, though, you've got to cultivate your own play level so that you have something to bring to the table. Build archetypes and play them against each other until you understand the strategy of each deck and you don't make misplays. Once you're there, then you should be able to gather enough associates to test against.