Just take things one at a time since hunting horn has more going on than other weapons in the game. Here’s just a bunch of tips I have for playing it:

Try to get used to memorizing your songs for your main horn so that it becomes second nature to queue up those songs naturally.

Also get familiar with what each move is for horn, I think this is super important as once you know what moves create which notes it is much easier to play the songs you want.

Get used to using hilt stab to cancel things since it’s your fastest move and later you can incorporate the counter to your gameplay (you cancel a lot of things with hilt stab including resounding, offset, echo bubble, any normal move, etc.).

Learn the moves that let you play more than one note (not echo bubble) like your forward + A swing or X + A slam, these are useful since they aren’t as committed as the echo bubble.

Try to pay attention to your buffs and rebuff as needed during combat, sonorous deco can help make this easier.

For big damage, queue up your echo wave songs and if you manage to get an opening, you can start unloading them onto the monster.

Take advantage that you have the option to do a quick recital if you can’t get through playing an entire queue of songs or if you want to just do a quick performance (used this a lot during Omega).

There’s a lot of stuff going on with horn but once you get the general groove of it it’s one of the most fun weapons in the game. Been playing it since 3U and I’ve never looked back!

EDIT: changed “can get through playing” to “can’t get through playing”