Does anyone here give lessons in shooting photographs?
It just takes a lot of practice
A fance camera helps, I shoot most with a Fuji X-T3 and a 50mm f2 lens and edit them a bit with Capture One, but to be honest, that's a bit overkill for this purpose. When you use your phone, just make sure to get enough light, but also not too much to destroy the atmosphere. And then maybe some light editing with Snapseed or similar apps and voila, done.
Here is an older shot done with my phone, S20+.
For wrist shots I would also recommend using the tele-lens if your phone has one, with the standard wide angle the watch will always look way bigger on your wrist than it really does.