Do not hold a grudge
Forget the evil that others are causing it, in a sense, the opposite of that people remember the good we do. So forgive should be just as simple as being grateful.
However in practice it is not. It takes a little 'commitment more. Forgiveness, in fact, needs to be justified : it is worth signing resented that colleague in the office made you trip him to shine his head? It 'makes sense to get out in a rash for that customer who, after having kept in suspense for weeks, eventually turned to a competitor?
If you think about it, the answer is "No, it is not sensible." And then adopts the "Strategy of Forgiveness" This undoubtedly contributes to make you live better!
Again I suggest a little exercise: try to write a letter of forgiveness to a person who made you nerves. Not to leave you overwhelmed by anger, with inevitable consequences on your mental health, will start to put you in the shoes : what may have been the reasons for his action? Perhaps the fellow was just trying to not be fired; or that client could not say no to a friend.
If you move the focus from the evil they have done to you the causes why people have hurt you, you realize that no one had the intention to harm you. One more reason to forgive and move on with your life without hesitation. Let's get on with the next step of the art of being happy.
Sharpen the negativity
Negative feelings represent a major obstacle to being happy. The psychologist Jonathan Haidt says that you can control the mind to be more positive . He uses this comparison: the thoughts and feelings that guide behavior are like an elephant; man, even if weak, can exercise control on the elephant!
Of course control the elephant (aka the mind) requires great effort and concentration, but everyone is free to adopt strategies he wants. From the techniques of meditation oriental, to control breathing, yoga, etc. anything goes, as long as the result is to be able to counter the negativity.
Remember that money can not buy happiness
For sure you will have objections. If your income is below the poverty line, it's hard to be happy. However, it is wrong to think that the level of wealth is directly proportional to the degree of happiness.
The examples of this are many, just think of celebrities who also recently took their own lives while having money and popularity.
In fact, the money allows us to buy the things that momentarily give us the illusion of being happy . As soon as the excitement for the purchase runs out, even happiness fades. So look for happiness in the possession of tangible things, does nothing but turn away from the true goal (how to live happy) because it keeps us in constant tension towards a joy that is only ephemeral, moreover resulting in a waste of energy.