There is science in this field, the writer of the linked article seems to be forming "broscience." Not to say that the list is wrong, some of it looks like worthwhile practice I have seen in other places. Personally, I prefer the science. Some things I've been reading lately
http://sonjalyubomirsky.com/papers-publications/
Note the papers linked down the page. Also search "Lubomirsky happiness pdf" for summaries. The pdf part is necessary only if you like to save things to a pdf library for future reading, for just browsing, can do without it.
http://en.wikipedia.org/wiki/Flow_(psychology) Link keeps messing when I cutpaste, just click on the "did you mean" link.
Some interesting summaries of the Flow experience can be found by typing in "Csikszentmihalyi flow pdf"
A great place to start is the old classic "Psychocybernetics." That book was written by a plastic surgeon who found that once his patients' physical defects were fixed, they were still unhappy. There are numerous summaries on the net, and I found a pdf of the whole book away from those obnoxious pdf sites. It's a little dated, but science based, easy to read, highly recommended. On an opposite note, I recommend against the "7 Habits of Highly Effective People" type of business books that pertain to this topic. They are unsubstantiated bunk IMO. Stick closer to science and timeless wisdom. Trendy business books I rarely find to be of much value. A couple of exceptions are Jeffrey Pfeffer's "Power," and Lehr and Schwartz, "The Power of Full Engagement." As an aside, I buy books off ebay and at sales. Sometimes use summaries from the net. Never pay retail for a book today unless you want to build a library and are loaded with no worthier cause to give money to.
For me, one important part of happiness is limiting the media and other messages that pour into my brain. This means very limited television, movies, magazines, which are crammed with negative messages (to get you to BUY) even in sports, choosing positive music (for years I listened to too much angsty, depressive, angry music such as Radiohead, NIN, Cramps, which are fine... in small doses). Also saying goodbye to video games and online gaming. If you take in constant unhappy stimuli via media, video games, music, is it any wonder you feel less happy over time?
Another tactic useful to me has been external focus on the wisdom of others and meditating on the lessons learned. The external focus can be the Bible, Buddhist texts, Koran, or the works of a philosopher. For me, I use the I Ching, not as a new agey fortune telling or feng shui mysticism, but as a way to focus thoughts and see the world from different angles. Not as, "what is going to happen in the future?" but "what is happening right now and how many different angles can I get on it?" I take an I Ching reading and then internalize it over days, weeks or longer, until the shift in perspective becomes a natural part of my thought patterns. Have been on the same reading for 2 months now, meditate on it every day. When it's time, I'll do another. Another great external focus is Thomas Cleary's three volume "Classics of Strategy and Counsel" out of print, but well worth getting off ebay or elsewhere. Pick a proverb from one of these and truly make your day about that, try to see experience through the lens of that wisdom. Review at the end of the day, and next day, stick with that proverb if there's more to learn, or pick a new one.
Setting specific rituals into ones life, such as "bed by ten, up by six," "exercise 5 days a week with periodic exercise times during the day," "diet log of all food eaten," hell even "meet a new woman," can really boost happiness. Write them down and give yourself mental rewards as you check them off daily. Then reward yourself at the end of the week. A reward based feedback loop to instill happiness patterns is important.
Time management is key in happiness. Pomodoro Method and Getting Things Done are good, science based time management techniques:
http://en.wikipedia.org/wiki/Pomodoro_Technique
http://en.wikipedia.org/wiki/Getting_Things_Done
Long enough for now. Could write lots more, self-hypnosis, heuristics, Gendlin Focusing, also good google search fodder, as studying and self-refining personal cognitive process is a hobby of mine.
The takeaway is that happiness and loving life are manageable quantities, well within our control, despite that some people are genetically predisposed to be less happy. Big brain uber alles. Instinct, predisposition, compulsion and habit, completely malleable and also chosen.