How can I make my nose stay in place and not widen so much when I smile? And how can I show more teeth? (photos)

When I smile i feel my muscles in my whole face is tightning. My smile doesnt feel natural. Why is this? My nose expand alot and I Dont know why ? When some people smile it just stays in place without little expansion. Also when I smile i only show half of my teeth I want to show much more. What can I do to get a natural beautiful smile With alot of upper teeth showing and not so muscle activation in my face.