An author's ability to help a reader relate to a character in a text illustrates the author's ability to create realistic characters. Readers tend to relate to characters who they can engage with on a mental or emotional level.
Relating to a character in Suzanne Collins' The Hunger Games requires a reader to empathize, sympathize, or believe in the reality of a character existing in his or her real world. In order to relate to Katniss, Gale, Peeta (or any other character), one must be able to understand the position the character is in, understand the feelings of the character, or possess empathy or sympathy (feel sorry for based upon experience or emotions) for the character. Relating to a character cannot be forced. It happens naturally based upon the reader's natural connections to specific human emotions and experiences.
I would suggest finding a character that you can relate to or share an experience with. While I am pretty certain you have never participated in a competition like the Hunger Games, you may have a competitive nature or a skill similar to Katniss'. You may have felt torn between two people (as Katniss is with Gale and Peeta). You may have had an older brother or sister leave for college. Whatever you find, you need to find that you care for the character and what will come of his or her life. If this happens, you have successfully engaged with a character.