Captive breeding is a very succesfull way to reintroduce the population into the wild. Not only that, but as the numbers rise, it then becomes easier for the huge cat to find a mate and further multiply the race. Some endangered species teams have special wildlife and habitat management techniques that require a lot of hard work to protect the species as well as it's environment. Sometimes Sanctuary Reserves are created and land set aside for threatened animals so that they are protected from hunting. Often, the jaguars are dropped nutritious fofrom trucks or helicopters to increase the survival rate in harsh winters.
Recovery plans differ from species to species.
Not understanding that endangered species do effect us in some way or another is part of the problem. Even if that just means understanding that the jaguar, along with other endangered species, is threatened with extinction, and not buying any products made from them. For the more serious and concerned individual, start off by research, learning everything possible about the species. One can then see what things impact the animal for good as well as bad. There are many ways we as a society can help.