When you want a character to be real, you have to make them seem real. And there’s no better way to do that than to give them some likes and dislikes. While this is one of the more important features in adding realistic traits, it is also something that doesn’t have to be over the top.
Likes and dislikes can vary from just about anything: food and drink, vehicles, toys and games, even other people for that matter. The best way to display these likes and dislikes is to commonly present them with the character throughout your story. An example is someone who loves beer. To show that they love beer, have them drinking it at least every other chapter of the story that they are in, or every chapter if they aren’t seen as much as other characters.