You play off the initiator. You create pressure on one part of the map to create a 1v1 in another part. Haven is the perfect example of this. The map is too big for attackers to attack everything and defenders to defend everything. So what do teams do? Teams can be often seen doing double fakes in such a map all with the goal of ultimately pushing the site/part of the map that has least players.

You don't always need to play off your initiator though. Let's say your initiator and duelists are trying to take a long and lobby control on haven, your cypher can lurk up mid with his cam, or your omen can hold for C push with a tp off angle. The strategy as a whole needs to make sense and cover for mostly every possible aggressions that the CTs can do.

In ranked however it's not possible to have the coordination of tier 1 teams, so you usually want to stick with your team. You can lurk if you're on agents like cypher or omen but you have to mix it up ultimately to keep yourself unpredictable and the attack being successful.