How not to be angry with anything, anyone, etc

After a few years of attending my spiritual class, I was taught how not to be angry. The roots cause of anger may be several factors, eg

1. When the persons you are dealing with do not fulfil your expectation.
2. When one's pride or ego is hurt by insult, rivalry or whatever.
3. When things do not turn out the way one prefer it to be happen.
4. Jealousy, greed, hatred and grudges.
5. The pride or ego of looking down of others. Majority never dare to be angry with those you feel more superior to you or to our loved ones.

Therefore as the reasons for angry has been revealed, there shouldn't be much problem to conquer anger. What so difficult to conquer anger er? Just accept the fact that all human population are not only not perfect yet with many many flaws. Everybody including me is full with all vicious thoughts. Whatever happen is nothing new, it is all Law of karma at works. 98% is predestined, 1% is effort, and another 1% is luck. Please inform me if I am wrong.