It's not something I know a huge amount about but there are definitely a few things you can try to make it easier. This article has some good tips: -
http://cameraergonomics.blogspot.com/2018/10/photographing-birds-in-flight-with-sony.html
It is hard though - especially at longer focal lengths - so don't be surprised if your hit rate is low
Highlights from the above article:
* Lens focal length. I find 300-400mm (equivalent) often useful. 600mm is usable but requires a lot of practice just to keep the bird in the frame. Any longer will not be useful for most birds in flight.
* ISO (C1) Auto.
* ISO AUTO MIN SS (C2) Faster.
* P Mode.
* Focus Area (C3) for bird-against-sky I use Wide. This is to allow the camera to focus on the bird anywhere in the frame.
For bird-against-background I use Flexible Spot L in the center of the frame. This is because [Wide] will focus on background trees, foliage and similar.
* Function Button items: AWB, DRO Auto, Center Lock-on AF OFF, Shutter type Auto, Creative Style -2, 0, 0, Metering Mode Multi, Grid lines OFF.
* Steady shot (cross keys left) ON.
* Drive Mode (cross keys right) Continuous Mid (10fps). Why not continuous High (24 fps) ? This after all is the RX10Mk4’s party trick which no other camera can do.
There are two reasons I stay with the 10fps speed.
First, 24 fps generates so many frames so quickly they become a burden when time comes to review them in post.
Second, I get a slightly higher keeper rate at 10fps.
* Quality (cross keys down), I have tried both RAW and JPG X-Fine. JPG allows you to shoot more frames in a burst but RAW allows more control of highlight and shadow detail, sharpness…etc in post processing.
* Disp (cross keys up) Clear the screen. Level gauge off, on-screen data OFF, grid lines OFF.
* I activate AF with the shutter button. I do not use back button focus. Others like to use the AEL button to initiate focus. But I find that the process of capturing BIF is demanding enough without having to remember to press two buttons.
* Focus Mode rotary controller. That is the sneaky little dial bottom left on the front of the camera which I frequently forget to change because it is out of sight and therefore out of mind. Turn it to C.