The BBC did a programme a number of years ago "Making Slough Happy" the conclusions came down to 10 steps. Feeding the birds is one of my 10 steps.
The 10 steps to happiness
Plant something and nurture it, care for a pet
Count your blessings - at least five - at the end of each day
Take time to talk - have an hour-long conversation with a loved one each week
Phone a friend whom you have not spoken to for a while and arrange to meet up
Give yourself a treat every day and take the time to really enjoy it
Have a good laugh at least once a day
Get physical - exercise for half an hour three times a week
Smile at and/or say hello to a stranger at least once each day
Cut your TV viewing by half
Spread some kindness - do a good turn for someone every day