Relationships in this modern world seem to be a short lived thing, not usually lasting more than a few months, with true love becoming rarer and rarer. Why is it so? Our generation is a rash one, running into things headlong without giving it a second thought. But ah, isn't love just the need to be held by someone, to be with them? While that may be true, to make a relationship work, a rational aspect has to be present as well. The irrational elements to avoid are radically changing yourself, unrealistic expectations and a belief that it will all just work without any effort.
While in a relationship, one has to change themselves to fit with the other party. It’s normal, as it would be impossible for differences to not exist between people, and overcoming these differences will make the relationship more stable. However, there are certain traits about yourself that just makes you, you. These qualities are a fundamental part of yourself, and if they are required to change, then it is simply not worth it. You’d be lying to yourself, denying your true nature. A relationship like this has no chance; unfortunately many people find themselves in this situation, and without a way out.
Also, unrealistic expectations can doom a relationship. More and more, people are just rushing into relationships without even really knowing who the person is, just a general idea on what little they know of them. These individuals commonly expect the person to be perfect, and to act as they believe they would. When faced with the realization that the differences between them might be too great, they have two options; to deal with it or to move on. However, many people seem to choose a third and incorrect route, which is to force them to change. You simply can’t expect them to so drastically change themselves. You would end up being with someone who is just a shell, suited to your needs, a mere scrap of who they really are.  
Another idea to avoid is believing that it will all just work without any effort. Love is something that needs to be earned, not bought or found. It rarely just clicks, with it all being fine. Nothing good ever comes easily. You need to build trust and respect by being there for them, and keep in mind that these are easily lost, and nearly impossible to regain. People are unwilling to forgive, as they are worried that the same mistakes will be made again, and in the area of love this can be very painful. You can't take anything back, so think things through. If you do not put in any effort, it will just fall apart.
Being able to see clearly in a relationship is key, as love is a fragile thing which can be irrevocably cracked. This reckless generation is going to have to learn the hard way what this all means. Fortunately, learning from our mistakes and pain is one of the quickest methods to getting something into your head. Here's hoping that we can all pass this class!