Whyever not?
(The only way to actually guarantee more happiness in the world today is for me to be happy.)
It's a choice i make.
When I first open my eyes in the morning I have arranged that I see something beautiful which makes me feel good. Flowers, always. A card from a friend, a photograph, a piece of paper with something written on it - for a while I had 'This is the day I have been given, let me rejoice and be glad in it'. The little baby food jar painted with spots is one of a collection given to me one Christmas filled with sweets by Laura who couldn't afford to buy presents that year - I have always treasured it.
What will you see when you first open your eyes tomorrow? If you have lots of clutter on your bedside table get one with a drawer in it, or put a basket underneath it and tonight put something there which will make you feel happy!
It's the simple things.