You also have to do those faction missions regularly. It compares your score to others in your chosen faction to figure out your rank. If you work yourself up to a street boss, and then never do any more, someone will eventually outrank you ans push you back down to a lower rank. Keep in mind the faction that you are in also plays a part. If you are a member of the Wolves for instance, they are a much more popular faction with like 10x (or more) the number of people than other ones. it will take you 10x (or more) the work to move up in that faction to get a higher rank and higher pay. Choosing a less populated faction will let you rank up faster for the same amount of work. Payouts are also determined by the rankings of the actual factions. People in the most popular faction will make significantly less per day than someone of equal rank in a lower faction. The winning faction gets you access to the bonus missions at the end of each month, but the lowest ranking faction gets you the highest daily income per day for the entire month.
Factions also reset at the end of each month, so it is a bit late to really worry about your rank at this point. It will reset tomorrow and you have to start all over anyway.