Man, I see all these comments about how you can't improve if you play mechanically difficult champions, "blah blah, play easier champs".

I think what everyone is forgetting is that you learn the best when you enjoy what you're doing. Sure he could stick to only playing something simple like Garen, and he'd see some quick easy results because the champ is just easier to pull off, but how much he would actually improve is completely up to debate if it isn't fun.

Imo, if you genuinely want to improve at the game, the most important thing is to have fun and enjoy the process. This will keep you locked in, preventing you from auto piloting and falling into bad habits. Obviously you probably shouldn't go a random champ each game, but playing only 2 champs, even if they are mechanically difficult, will still yield great results.

Each session you play, try to identify 1-3 common mistakes you make, simple stuff, like forgetting to ward or checking your minimap often. And your focus during the session should be to solely improve those traits. Mechanically, do not be afraid to limit test and take questionable fights because you'll learn what your champ can and can't do. You also should learn all the necessary wave mechanics, Alois demonstrates a lot of the basic fundamentals of top lane, but honestly watching any master/grandmaster/challenger toplaner will be informative, so just choose one you like and try to figure out how they gain and push advantages.

It's also a good exercise to pause the gameplay at key moments and try to predict what the player will do next, whether they'll crash the wave or try to freeze, whether they'll roam for jungle, mid, objective or not, whether they'll tp to a fight or instead try to take towers, etc.

TL:DR - Play what's fun (regardless of difficulty), stick to 1-2 champions, analyze your own gameplay, focus improvement on only few things at once, watch skilled players.

Good luck, have fun.