Exist. It doesn’t really matter what you bring to the table so long as it’s anything remotely tolerable and/or different than The Person Whose Shadow You Are Existing In. Just be smarter/better looking/funnier/nicer/taller/more laid back/something; all that matters is that there is something to attach to that differentiates you in some manner. Effortlessly move into The Person’s shadow.
Enable. Realize that the person whose affection you are courting is irreparably damaged. Be okay with this. Earnestly believe that by “being there” for that person, you are respecting yourself and setting yourself up for something other than a complete emotional trainwreck. Set a precedent that enables this person to constantly talk about themselves and their ex(es). Give an encouraging shoulder rub or deep eye gaze to establish that you’re listening.
Start to hate yourself. Try to figure out why you were overlooked for someone less smart/good looking/funny/nice/tall/laid back than you. Worry that there is something terribly wrong with you that everyone notices but you’re oblivious to. Check your breath. Get a wax. Make a habit of drinking too much. Start to smoke inside your apartment.
Become obsessed with The Person Whose Shadow You’re Existing In. Google them. Find their blog. Find their LinkedIn. Find pictures from their study abroad trip in 2005. Make one of your friends add them to Facebook so you can look at their pictures. Start to doubt that you are smarter/better looking/funnier/nicer/taller/more laid back. Feel like killing yourself when you realize the last they communicated with your love interest was twenty minutes ago. Tweet something about wanting to kill yourself.
Be actively yet privately hateful. Text your best friends that you wish the person would die in a car fire. Come up with an unflattering nickname for the person and refuse to call them by anything but. Make macros of the person’s profile pictures with rude captions that criticize their weight or appearance. Show their picture to people and say, “How nasty is this person?!” Try to convince yourself they’re sincere when they respond with an obligatory, “Soooooo nasty.”
Call your ex. You know, the one who will make you feel better about yourself. Solicit compliments. Make idle plans you know you won’t keep.
Embarrass yourself. Get too drunk and burst into tears in front of your love interest. Feel humiliated because you can’t tell them why you’re upset. Feel completely squashed by the fact that they’ll never truly love you or even care for you in a meaningful way because they’re in love with someone else. When they ask what’s wrong say something about your mom getting diagnosed with diabetes or work being really stressful. Do not mention your emotions. Feel embarrassed that you have emotions at all. Try to stifle them. Cry in your car and at movies and in your apartment while you are conducing your hourly stalk of The Person Whose Shadow You’re Existing In.
Never, ever move on. Hang on forever. Allow yourself to be wholly disrespected while you essentially lay yourself at the feet of the person whose affection you’re seeking. Take what you can get. Damage your relationship with your friends by constantly talking about your “situation” and The Person Whose Shadow You Are Existing In. Eventually meet someone you’re vaguely interested in and pour all of your hopes, dreams, anxiety, and unrequited feelings into that relationship. Prepare yourself for the fact that you might just end up repeating this cycle all over again.