I used strategy and it felt good

This was really cool for me, an amateur. I played for development, then started a king-side attack, rotating my knight all the way to h5. I don't think I made any huge blunders. This is the first time I moved my knight to an ideal square, and the first time I've felt my king side attack working just the way I wanted it to. Black eventually lost on time because he spent 5 minutes thinking after 21. Nh5. He freaked out a little his last move as he was low on time but Rh3 was coming anyway.

Where could black have refuted my attack, and what could I have done better?

looks quite ok, well played!

I dislike your 7 Be3. What would you have played after 7...Ng4 intending a possible 8...Ne5 and 9...c5?
I dislike your 9 Qf3. What would you have played after 9...Nbd7 intending 10...Ne5?
Nice finish though.

I don't like 11.Nf5 because after the following piece trades, he manages to advance d6 and you get a weak e pawn. Strategy involves also pawn structures. You would have been in trouble if he had blocked your e pawn.
19.e4 and 20.e5 were decisive, well done there!

@tpr i disagree on 7. Be3, after Ng4 Bf4 the N has no great use on g4. If it goes to e5 it is subject to f4 ideas.

However i also would not have played 9. Qf3. Instead 9.Bb3 looks more sensible, in order to take the motif Nxe4 followed by d5 out of the position, then maybe Qe2, Rad1, etc. Bb3 could also have been played earlier.

@pavlito83 the e-pawn seems not so weak here, because white had a development advantage. So i think Nf5 is ok.

Great game, @tpr I see why you dont like Be3 the second I saw it I thought about dragon sicilian with white, where you can play f3 first to avoid Ng4 and then Be3. But in this game its probably an ok move.

I'm not a big fan of 17... Nxd3 That bishop was bad, and the f pawn is blockaided. 17... Re8 or maybe Qe7 would both be solid. Black is just fine in this position, and white doesn't really have any attack left. Maintaining that knight was important for black.

The position started to collapse when e4 and e5 were invited.

21 Nh5 is not the most accurate. The position is screaming for an immediate f6, but nevertheless white remains dominant.

21... Ng5 was a mistake and could have been punished with the h pawn.

Towards the end black should have tried to sac the exchange and maybe come up with a fortress.

The final position is wow losing for black on multiple levels... The king is in such a horrible position. A rook will soon come over to the h file to end it... and if that is some how stopped by a miracle move then the knight is moving and the queen is mating on g7...

As far as "strategy" I think you didn't really need much strategy after you got e5 in it's all tactics.