A Stronger Mind: Basic Steps for the Naïve
I'll be honest, I can't be the only person who has had their ego checked, been rejected, peer pressured, manipulated, etc. Experiencing these social woes, and overcoming them is arguably a precures to being a well-functioning adult in society. In fact, perhaps it goes without saying that those who fail to overcome such dilemmas are doomed to fall victim yet again. Speaking only for myself, I often feel as though my transition from a timid, soft spoken boy desperately attempting to imitate a man to where I find myself today to be far from the most profound of metamorphosis, but a commendable one nonetheless.

Go where you're celebrated, NOT where you're tolerated!
Well, pretty basic information is it not? Hmmmm. If I were to ask my past-self whether or not I shape my life around this basic idea, the answer would be a big fat no. Alas, not all humans are born with the intuition necessary to identify those who simply put up with your company; be alert, there's more people looking to prey on your naivety than you could possibly imagine. For those who don't know whether or not they fall into this large category of victims, I ask you one simple question, "Do you find yourself being introduced to new people via your friends, friends?" If that answer is yes, well, at the very least you're looked on fondly enough to be presented to others like it's yet another day of show and tell.
A second question I would ask comes directly from a lecture by Jordan Peterson, who is adamant supporter of the idea that true friends celebrate good news, and listen during bad news...From personal experience, the utility of such bonds far exceeds the value one may have from a half-assed social circle. Reap a better tomorrow by investing time into great friends.

Assertive, assertive, assertive!
For whatever reason, the people I am closest to are ironically the ones I least tailor my speech for. I'm not psychologist, but this sounds almost counter-intuitive on the surface. However, I believe what has been conflated by the more passive folk is that common courtesy is the same as barring themselves from acting in self interest—it is not. You will find yourselves easily manipulated, or perhaps even viewed lowly. Of course, none of these are the worst case scenario, the worst case occurs when those around you begin to outright resent your uncharacteristically-high standard of generosity. At this level, not even a narcissist can be bothered to spend their time preying on you. You want that job? Take that job, don't let someone else step in front of you just because you aren't confrontational. On the contrary, how else can you ever know whether or not confrontation is even warranted if you're always abstaining from the path with most uncertainty...well, you won't. As Plankton says, "No, No, Be Assertive."

Enjoy time with yourself
It is too soon for me to tell for certain whether or not this is the most important piece of advice on this list. Keeping yourself company is a treasure, and this is simply due to the abundance of time one may spend in deep rumination. As time elapses in this state of intense contemplation, you begin to better understand yourself and your surroundings. You'll experience an intrinsic value which is seldom replicated through external means.
Keeping it simple
No one said this was going to be a deep psychological analysis with ample research like you may observe in Shane Law's posts. I did say however that this piece would a brief trip through my personal strategies to overcoming the most despised aspects of myself. It is strange how things seem so different in the distant past, but hardly any change is seen day by day. This is why you should begin to make the simplest effort to better understand yourself, and why you may often be among the few uninvited to the party, the many feeling insecure about speaking their mind, or they innumerable population of people incapable of understanding why they don't appreciate themselves when they aren't even making an effort to actively appreciate themselves by being their own company.