I would say one of the biggest difficulties with learning keybinds is just the fact that you're going to get more. The only real solution is you have to evolve once in a while. Once you start picking up more abilities than your starter bind can handle, it's time to assess what you need or don't need, what you need most, what you can group together, etc. The more familiar you get with the game/job, the better you're able to judge how to handle your space.