These suggestions are not mine but are from the scientific findings of EW Dunn et al. They are valid suggestions which even without reading have been practicing. What are you take on these suggestions? Do you have more to add to what the researchers have discovered about this?
I started doing more expensive than material things and my life has became a little more happier so they aren't lying with the first point. Instead of buying something for yourself during your birthday, take a vacation to go see places around the world and see the difference it adds to your life, whenever you remember those experience you'll smile.
If you want to become more happier in life, make others happy and you'll be happy too. We're in this world to make others happy not only ourselves. Don't be selfish, concentrating on yourself can be very toxic. Always make people's day and you dat will be filled with happiness.