1 . Spacing is determined by matching your legs space with your shoulder to shoulder distance!!
2. Pronouncing NEAH (willingness) and calling ALLAH AKBAR loudly for late comers are two wrong things that happen in our Masjid.
3. 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.
4. Don't rush and don't be too slow (it is JAMA'H prayer) go with Muslims in timely manner (in the drawing above it is almost end of Fatihah and some one is still in Sujod)
5. 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.
6. New line start MUST be directly behind the IMAM wherever he is. People start their Jamma Salah some times in a corner. That is wrong.