Try imagining your life without all that you presently have. If you can master this ability, then you will appreciate what you do have to such a degree that you will live a life of constant joy.
If you were lost in a wilderness without food and water - and then found some bread, you would enjoy that bread more than the most sumptuous meal! Rabbi Simcha Zissel of Kelm wrote that he personally had such an experience, and it was like living in paradise. You will always be able to feel that joy if you use your mind wisely.
Today, spend a few moments imagining what it would be like if you had absolutely nothing: no family, no friends, no possessions, no money at all, no knowledge, no eyes, ears, hands, feet - absolutely nothing. Continue this exercise until you actually feel it.
Then do the second half of the exercise: Imagine yourself obtaining what you presently have, one item at a time
(see Chochmah Umussar, vol.2, p.74; Pirkei Emunah, p.20; Gateway to Happiness, p.46)