I must confess to having a small problem. One which I imagine you may have encountered also. Whilst at university, I have a plethora of possibilities open to me, with regards to building relationships. There's no lack of students and I imagine that in the future, many of them will be in positions of power which will make them rather useful. For now, however, many are quite the irritation. How can I separate the wheat from the chaff and put in the least amount of effort required in maintenance?
Admittedly, my best advice on this subject is simply trial and error. It is a skill, an innate talent, that will take time to cultivate. You will get better at it with time and experience. There will be misjudgements, and if you are conscious and intelligent, you will learn from them.
Culling my social circle to that of optimum performance vs. maintenance has taken time and much scrutiny. I have found it necessary to re-evaluate my tactics, my standards, and my selections as my needs evolve and situations change.
It is a matter of becoming adept at adapting and social manipulation. Be aware.
It helps to maintain a charismatic persona on the whole. Being well liked and admired is an all-around advantage. You will have to put forth less work with individuals, if your reputation proceeded you. If you are a person others want to like, they will like you without you needing to give them personal incentive to do so. Their disposition toward you will be positive, and this is an advantage you will always hold. You will be a person they remember, perhaps months, years down the line when you may require their leverage without having to expend excessive energy and endure potentially fruitless pursuits.
It also helps minimize the time you need to spend on the what-ifs and the could-bes. Those people you see holding some ounce of potential for the future, who are currently not up to caliber, or who may just as easily fall to the wayside. They can be dismissed with no fallout, as there were little to no ties to sever.
Being admired in general and commanding attention and respect is a strong foundational tactic in constructing a powerful social orbit.
Prioritize. What is it you require? Seek out those who already exhibit the traits or hold the assets you desire. In an ideal world, we would know and be ideal people. Your time is of value, spend it on those that have the most payoff. Cut your losses. Be flexible.
Evaluate individuals. If it helps? Dissect them. Weigh their pros against their cons. Pit them against one another. Develop a system of ranking and scale, which will in turn help you delegate your attentions, time, and effort toward those that are most useful and most enjoyable to work with.
This has become a tad disjointed, and I apologize, but amidst this jumble are tactics and habits I have found myself adopting over the years that have simplified the sometimes overwhelming scope of social opportunities and helped significantly reduce my wasted time and tried patience.
I have made mistakes. I admittedly still do, though they are certainly less frequent now than five years prior.