I would like to be grateful via /r/gratitude

Can somebody help with tips on how to be grateful. So far everything I practice is surface level. I have a huge complaining issue. I take everything for granted and I've been unhappy because of it for as long as I remember. My confidence is down the drain and I'm in a bad mood all day since I'm so ungrateful. Id love some help on how you became positive and grateful! Thanks!!