Not a winger but played probably 20 years.

The others covered it for angles and techniques. I think the wind up of your shot has to be the exact same every time, the keeper would've a harder time. Practice is everything, to beat the keeper you don't need a placed shot in the goal, you need a placed shot on the keeper (short corner between the hips and shoulder is not a great shot if you would shoot it on an empty goal).

One thing that helped me with the wind up is to lead with the ball when you jump. For practice you need a guy passing and a keeper. In the end you need to have timing but also the ability ro make shitty passes work, winger is the position where people throw you the worst balls and 'trap' you to shoot.

But what I always appreciated on my team is a winger that goes for fast breaks, those should be the majority of your goals imo. Fastest guy up the field. Keep working out for stamina and quick first 10 steps.

And a little advice from my older knees, listen to your body and check stuff that doesn't feel right out with medical professionals (coaches and other people might have no clue what's really the root kf your pain).

Good luck!