How do I overcome jealousy? What really causes jealousy?

When you compare yourself against other
you are vulnerable to become jealous

The way I started battling jealousy within myself is by understanding where it stems from. Jealousy comes when you compare yourself with others. The antidote to this, is to understand that just because an apple is more popular than an orange, thanks to Apple Inc, does not in any way make an orange less important or insignificant. Both are essentially fruits and it is intellectually insane to compare them against each other. 

All we need to do is to understand that our life's journey is totally different than that of others and when we accept the truth that just like others have their own set of strengths and talents, we too have within us, some really awesome and unique bunch of talents and strengths. 

Understand, the person who is blessed more than you is not better than you, the problem with jealousy is that it ends up making him/her superior and makes ys feel inferior, even though we may not usually think about ourselves that way. The end of jealousy is to love yourself and to be focused on your own progress than looking at others with awe and then wonder 'WHY not we and WHY them, always', after all an apple may have a more sexier appeal among fruits but it is no where a match, when it comes to the Vitamin C content which is where orange nails it (if you know what I mean).

What '5 don'ts' have I learnt from people's failures?

Best lessons are learnt when life knocks you down
as opposed to when you are at the top of everything

1. Whenever you follow people's advice or suggestions on the cost of your own inner drives, you are making a mistake that will lead to tougher times of self-doubt. Worse case scenario is when you ignore your stronger vibes coming from within about a particular matter just because you are conditioned to listen or pay heed to what your elders, friends, or your colleagues think about what you should do. Lesson to be learnt - Follow your inner wisdom and make sure that your decisions are in alignment with your values and beliefs and not someone else's values or beliefs. Even if you take a wrong decision, you will not blame others instead you will evolve through it and become better than before.
2. See things as they are but not worse than what they are. In times of crisis we tend to make this mistake. We become overloaded with stress or emotional breakdowns and the byproduct of this is that we magnify our problems to such an extent that it ends up becoming a real issue (even though in essence it is not) and eventually we lose control of the situation thus allowing that matter to become the centre of our life around which everything starts revolving
3. Most people end up becoming shortsighted in terms of plans, actions and vision. In many people's case I have clearly seen that enjoying short-term-gratification and sacrificing long-term-value-addition leads to an unsatisfactory life. 
4. One of the most common ways that most people despite of earning millions, traveling the world or becoming CEOs of major corporations end up becoming frustrated as oppose to happy and cheerful, is when one becomes too superficial and loses complete touch with the spiritual side of life. Spirituality is a necessary ingredient for a balanced life. 
5. Lastly, not knowing oneself or failing to understand one's strengths or weaknesses and just going with the flow (like a dead fish) is a path that will guarantee failure. I remember reading a quote from Sun Tzu that resonates with this thought, it goes something like this - “If you know the enemy and know yourself, you need not fear the result of a hundred battles. If you know yourself but not the enemy, for every victory gained you will also suffer a defeat. If you know neither the enemy nor yourself, you will succumb in every battle.” Although, this quote is more applicable under the context of a War strategy which is precisely what Sun Tzu was into. But I think it is equally applicable in the war that we common people fight everyday.