Feats

Feats are no longer something you get by neglecting an ASI.

If you want a feat, you have to work for it.
Say you want the Sentinel feat. To work towards that you have to do oppurtunity attacks or something similar.
PC's can 'passively' learn feats by doing relevant things that are associated with said feat. This can be done by:
The player decides on a feat that they want their character to passively learn in this way, the DM assigns things that will grant progress points towards this feat. When a set amount of points (1000) have been gathered, the character gains the feat and the player chooses another feat.
For example, say that one wants to work towards the 'sentinel' feat. The feat centers around being on guard and making opportunity attacks.
Logically, making opportunity attacks will grant you progress towards this feat. Being near an ally when they are attacked also grants progress (because your character is going 'shit, maybe I could've done something about this' and is starting to pick up on the fact that when an enemy attacks an adjacent ally, you can use that to your advantage).
In addition to these 'feat specific' ways to gain progress (which will be different for every feat), there are also just general ways to gain progress: training/practicing/studying, where progress varies based on what you have available: studying for ritual caster will go quicker if you have a good book on it, training for shield master will go better if you have a sparring partner,... an NPC gives you some pointers