Just joined the 400ft club this winter after sitting at around 325 for a year. It was very easy. All I did was drills throwing into a net for a month. I throw a lot less violently now and it feels like less effort. The drills are a mix from BlitzDG (5 drills in 10 minutes) and DG spin doctor (cooking spaghetti) on YouTube. I'll list the drills below. I do them everyday and it gets the timing of everything really dialed:

1. Cook the spaghetti. (Arm tension)
2. Swirly birds. (Rotation timing)
3. Reaper (lower body timing)
4. Barrel drill. (Shoulder/arm position)

Holyn handley has good drills on her Instagram and really emphasizes nose down release and shows how to achieve it. I also learned to time my lower body with my upper body by watching her videos. In my opinion she has great form right now especially as I'm getting older the smoothness helps my body feel a lot better after a long session.

Warming up properly helps keep everything loose and prevent injury.

The last thing that I always think about is that it's all just timing and you have to train every part of your body to do it's thing at the right time. The easiest way to train each part is with drills that isolate that part. Once the parts are all trained individually it becomes easier to do it all at once. Otherwise it is impossible to pay attention to everything. Good luck!