I have the same problems, it is often very hard to shake enemys off, esp. if they are veteran pilots. Climbing is a sure death against good players.
As a chaser i just have to pull my nose up and have a big area to hit since the enemy plane is climbing up the sky.
Barrell rolls are also not effective, when enemys start barrell rolling i usually never follow but stay up and wait till they start crossing my FOV again. (And they mostly do).
On Sim Mode i try to use the terrain to shake enemys off, flying very low over dark areas and NOT climbing up again.
Its kind of weird since many dogfights take place so damn low, but if you gain altitude you are so easy to spot.
So i stay loooow and hope to distract my follower so he looses me.
If it comes to a turn fight, i do the same thing as you do, zero the throttle and hope the enemy shoots past me. (Only works with rookie pilots).
Vets shoot your arse up for sure.
To sum it up: Watch your six ALL the time, if you have a good player on your six you are doomed. (I know, since i get my arse handed to me very often
)
And since i don´t use good turn fighters i need speed and the terrain to get the sucker off my back.