I need help with these too, I've landed less than 20 in my life and they're a real struggle, so take what I say with a grain of salt. But these things help me a little bit:
Get comfortable with just rolling in the switch tre position, this is one of the things I struggle with the most, just setting up for sw tres is so uncomfortable but the rest of the trick is definitely easier if you can set up for the trick comfortably.
The tre is easier to form for me if my shoulders are facing forward in the direction I'm rolling, but harder to land. If my shoulders are square (which I think is the correct way), its a bit harder to make the tre flip motion go but I'm definitely set up better to land. So play around with which way your shoulders and head are facing and find out what works.
Experiment with weight distribution, how your trucks are leaning and whether your center of gravity is more over your front foot or back foot or even etc. For tres and sw tres I think I try have a little more weight over my front foot since my feet are so far back on the board already.
Like regular tres, I feel like sw tres shouldn't take thaaat much effort if you have the right setup and weight distribution and scoop in the right direction. There must be a sweet spot or pressure point of sorts where it just works, I haven't figured it out yet. But a lot of my friends do them with little to no effort and it just seems to work so I guess its just a matter of experimentation and practice.
If anyone that can actually do these has any tips that would be great lol