By definition you cannot do anything to increase a random encounter. If you are looking for something and find it that is not a random encounter that is a planned encounter. The Ranger making a survival roll is called hunting or tracking. That might allow them to “encounter” a wild animal but that is about it.
The way most encounters go both sides make perception rolls to spot each other. If both sides completely miss the perception roll there is no encounter. If only one side makes the perception roll, they can often choose to avoid the encounter. The way to increase your chance of an encounter is to increase your perception roll so you can spot the possible encounter. The way to decrease your chance of an encounter is to increase the DC of spotting your party.
The chance of there being anything to spot in the first place is up to the GM. There is not a lot you can do to increase the chance of an encounter. For encounters with other people, you might be able to spread some rumors to cause people to want to be or avoid where you are going. But those are doing so may result in encounters you don’t want. For example, spreading rumors of a rich ship with valuable treasure might increase the chance or other pirates in the area, or cause fewer if you are traveling a different route. You probably could use a wish or similar magic to affect the chance of encountering something, but the cost is going to probably be more than the reward.
I know I've seen some random encounter table sin some modules that say to increase or decrease the die roll based on certain skills or classes which may be in the party. There no official rule that I know of, but I could certainly see that someone could use survival, or stealth to find out about an encounter and give the party a way to avoid it, or prepare for it.