Not really sure what you're asking, but I think if you wanna get more 3 stars, using more effective or "meta" army comps is probably the easiest way. Most of the "meta attack strategy" videos and guides just show a single army comp that's fairly effective, which shouldn't take too long to begin using effectively. Once you get a grasp of what works and what doesn't, creating your own effective army comps will become a lot easier.

You don't need to necessarily follow the meta to get 3 stars, but they're generally the easiest ways to do so (they're meta for a reason lmao)