A person must understand that everything they have is given to them from G-d, and furthermore that G-d only wants what is best for us. He understands our unique needs and purpose in this world (on a specific level each person has their unique purpose which only they can fulfill). If we have a specific purpose then G-d Makes sure to give us all the "tools" we need to accomplish our purpose. If we look to our friend and wonder why they have the "tools" they have and we don't have the same tools we must realize it is simply because we have different purposes. Rabbi Akiva Tatz gives a wonderful parable to understand this point. Imagine that a contractor hires a bunch of workers to build a building. He hands each one of them a bag which contains tools. The worker who is supposed to build the wood frame to the building is given a hammer, nails and a saw. Next to him is standing the worker who is supposed to paint, he is given a paint brush, a bucket, rollers etc. Do these workers look at each other with jealousy? Does the painter wonder why he wasn't given a hammer instead of a brush? Of course not, there is no jealousy between them because each one realizes their job. In fact they would be extremely upset if they were given the tools of the other person. The problem is that we simply don't always know what exactly is our specific job and purpose in this world, but we must Trust in G-D that we have the tools necessary for our purpose and any other tools would prevent us from accomplishing what we need to do This is the reason that the Angels are not jealous of one another. They have absolute clarity in what their purpose is and they have everything they need to fulfill that purpose.

This understanding might be difficult to realize at times and to internalize.