I guess what you're aiming for is something like an altitude hold.
a lot of seasoned fpv-ers say to learn, you should get off angle/horizon mode asap,
and I have to agree...
as Ive got better at full-acro mode, what Ive realised is you intuitively learn the relationship between pitch/roll/yaw/throttle... unless you are in straight level flight, they never act independently.
I mean this kind of is obvious, but was highlighted when someone pointed out ....
if you're flying at 90 degrees forward (theory) , then yaw and roll , switch roles compare to 0 degrees.
so any angle between 0 to 90 , they are mixed roles...
(this you start noticing alot when you do things like yaw spins with higher camera angles)
the point being... you cannot 'know' this, most fpv-ers are not enginners/mathematicians calculating angles and vectors, they just fly...
and thats the way to learn... many, many packs, preferably everyday.
start up high, where you cannot hit anything, then get lower...
I think two things really helped me get an intuitive feel...
learning to hover - with wind... the constant adjustment, hones your stick feel.
learning to stop fast - yaw stops, and pitch stops ... I kind of think of this a bit like how a ice hockey player stops
going low and slow - really helps on throttle control.
(the slower you go, the more you will bob up n' down, as you touch the throttle)
I dont think 'tricks' help much... rolls, flips, loops, might feel like progress, but really they are not difficult (disorientation is perhaps the only thing) ... of course, this changes when you start doing low, through obstacles... but you have to be able to do all the above before that anyway
anyway its really just stick time...
Ive not been doing it long, but I do fly at least 4 packs a day (8 on a good day!) and it does become second nature after a while.
(if you cannot get out, use the sim - velocidrone/liftoff... its not the same, but does really help build muscle memory.)
so just do it, you'll be fine - it'll come together as you fly