When a person has a natural ability, such as drawing or writing, they excel as they use that ability more. Some people are lucky enough to be good at more than one ability and they excel at many things. It's not different for psychic abilities.
Someone that can see the future or predict the outcome of events doesn't mean they also see dead people or can read your mind. Future prediction is a psychic ability and communicating with spirits is another. There are countless psychic abilities from the ability to leave the body to understanding a person's true emotions.
Some people do have the ability to do more than one such as empathy and communicating with spirits. People also have different strengths and through practice can improve their natural abilities and the same is true of psychic abilities.
People that suppress their natural abilities may eventually lose them. They may not be able to control it and only get the occasional flash. If you use your ability more and more, then it will get stronger. It's like a muscle that gets stronger the more you use it. Future prediction is a bit different given that often people can't control it, but the best predictors are known for their accuracy.