5.) It's summer, make lemonade! Life is going to give you lemons, I guarantee it. What you do with them is what impacts your happiness. Back in 2006, after a breakup, I was sad, but there was nothing I could do about it. I could throw a pity party (two of my last standing single girlfriends got engaged around the same time) or I could make lemonade. I decided to use this as the catalyst to finally book my trip to Australia. Living well is the best route to happiness. Something bad happens, you plan something good.
6.) Don't put your eggs in someone else's basket. Waiting for your spouse, boss, child to do something to make you happy? This is a bad strategy. I usually do something nice for myself on Valentine's Day (see #5), but last year I had a boyfriend, so I figured he would do something. When he didn't, I was sad and disappointed. If I had been responsible for my own happiness, I would have had a great Valentine's Day. Most folks have enough trouble with their own eggs in their own baskets. Look after your own eggs and you'll have a better shot at happiness.
7.) Just do it! Often our unhappiness is caused by something we could fix - a job we could leave, a relationship we could end, a pile of clutter we could clean up, debt we could pay off, etc. But we'd rather agonize over it, worry about it, and let it steal our joy. Sometimes the best course of action is to suck it up and deal with it. Sit down one weekend and clean up the clutter or map out a plan to start paying off the debt and then do it. If you don't, choosing instead the short term pleasure of doing something else or buying something else, the situation usually gets worse and you're more unhappy. Sometimes you have to trade short term pleasure for long term happiness.
And finally, remember that happiness means different things to different people - for some it may be spending time with family, for some it may mean travel, for some work. Know what it means for you and strive to add more of it in your life.