You spend more time with them, often conversing with them. You become closer to someone by sharing your feelings, thoughts, hopes and aspirations for the future and listening to them. When one person loves another, they want to be with this person whom they love. This is true for whatever type of relationship one may think of. A mother and her new born infant, a father and his child, two friends, sweethearts, husband and wife.
Love seeks to be with the object of it's love.
This helps us understand the great mystery of our Faith. If you want to develop a personal relationship with Jesus you have to make an effort just as you would in your interaction with others. Jesus wants to be your best friend. He is the one friend that will always be there for you. He always loves you and wants what is best for you.