Bad smelling breath from mouth due to eating some type of foods (onions and garlic) or from clothes (socks, unclean clothes) are annoying to other people and should be avoided as per our Islamic teaching
Don't rush and don't be too slow (it is JAMA'H prayer) go with Muslims in timely manner (in the drawing below it is almost end of Fatihah and some one is still in Sujod)
Yawning during prayers is wrong, try to avoid it……….
Will you do this if you are meeting an important person at work?
Remember, when you feel like Yawning, that you are facing ALLAH so, try to suppress it and you succeed…. Respect your presence in front of Allah and HE will respect your salah.
The IMAM reads loudly and you should listen, but not that you read loudly and others are disturbed by your reading… in fact IMAMS reading is enough for all behind him.