Every illegal action can lead to more notoriety with the cops (or rival Criminal organizations).
This is the core of your RNG. The higher your notoriety the more eyes on you.
So things like illegal transports might fail more often or get discovered more often.
Staff might steal from you more, informants might get caught faster and cops get notified more of your illegal actions.
Notoriety decreases over time but another way to reduce your notoriety is to get yourself arrested by the cops while Wanted but that will give you the “Arrested” debuff which is a hefty penalty.
Not all your notoriety will be used for calculations, it really depends on the context. For example drugs related RNG will use notoriety related to drugs production, logistics and Criminal organization notoriety.
Types
There are 2 types of notoriety.
Personal
Any illegal action you take can gain you personal notoriety. Personal notoriety goes down faster then Organizational notoriety but will be combined with Organizational notoriety when performing RNG checks.
Organizational
Only applicable if you are in a Criminal organization. Your personal notoriety will be combined with the organizational notoriety when performing RNG checks.
Waiting will of course decrease notoriety over time but getting one of your Wanted members arrested also helps but the Criminal organization will gain the “Member arrested” debuff which is a hefty penalty.