How to be More Grateful for What We Have

The holidays are right around the corner and this is the season when people start to think about being more grateful and appreciating what they have. There are 365 days in a year so we shouldn't only be grateful around the holidays. What does it mean to be more grateful for what we have? Why is it difficult for people to be grateful but so easy for them to complain? What are the effects of being appreciative and complaining, and how can you learn to be grateful if you've never done it before?