You are miserable, lonely, hurt, frustrated and frightened.  You are alone again; or you have been with someone for 'x' number of weeks, months, years, and you've been unhappy just about the whole time. Your fights are repetitive, no one has discussed marriage or it keeps getting postponed, your sperm is slowing down or your eggs are drying up, you're not having sex, or you're having great sex but fighting bitterly in between every short-lived reconciliation. You try to travel together and one of you ends up flying back early, alone. You invite your girl/boyfriend to meet your parents and she/he bags out at the last minute. You blame everything on your partner, and vice versa. You talk about going to couples counseling, but it never happens. 
 
 

This is not a great place from which to start having that great relationship you say you want. You - yes, that's spelled Y-O-U -- have to change.  You have to get clear that you are a worthy, valuable human being, entitled to love and be loved. Your sense of unworthiness may be so deep and so unconscious that you don't even know it's there - but it's why you're lonely, or why your relationship is lousy. Get your self-esteem together, start working on repairing the relationship you are in and commit to it, get into that couples counseling already - or get out of it and start fresh.
 
 

So let's say you are starting fresh, ready for a new relationship. Having followed the advice above, you now believe in yourself, you have fully worked through your hidden self-doubt and self-loathing, you have reinforced your belief in your strengths, your goodness, and your worth, and you are not unduly focused on your flaws and weaknesses. And you are crystal clear: you want to get into a great, healthy, strong, happy, successful, intimate relationship. If you aren't really crystal clear about that - you haven't changed enough yet. If you experience repeated frustration and disappointment in getting to this healthier place, consider consulting a mental health professional for some deeper self-understanding.
 
 

But let's say you are in fact clear. Good, now start dating. You have to tell everyone you know that you are looking to meet someone. If you are 30 or over, you probably need to use the online dating sites. You might need to use online dating even if you're younger, but the older you are, the more useful those sites tend to be.  Forget bars, for the most part. They're more for hook-ups than relationships, and you need not to confuse the two.   
 
 

Next, you have to be a smart shopper. Yes, you are being chosen, or not - but you are also choosing. Be the chooser, and be picky. If someone turns you down, keep moving. And if someone is into you, it doesn't mean you have to be into them. You either are or you aren't - and if you aren't that into them, the sooner you decide to keep looking elsewhere, the better. You can spend 6 months trying to figure out if you really want to be with someone or not - but if you're honest with yourself, you probably knew it wasn't a go from day one, and you let fear and guilt stop you from saying "no thanks." And then you spent 6 months with the wrong person, when you could have had 25 dates during that time, one of which might have yielded someone you would have been crazy about. And now that person is no longer available, because you were wasting your time not breaking up with Mr./Ms. Wrong!   
 
 

Yes, you need to be really attracted to the person you fall in love with - but maybe some of your requirements - like no back hair, or extra large breasts, or a minimum of $3 million in conservative investments, and other overly-specific demands - maybe you need to be a little flex on some of those things. And bear in mind, you've probably already had horrible relationships with people you were intensely attracted to, or people who seemed to be able to provide you with everything you wanted, so physical attraction or plenty of dough, by themselves are not enough. Is this person kind, supportive, excited about you and your dreams and goals - and vice versa?  Do you share common tastes, preferences, interests?  Do you imagine enjoying the same kinds of activities and lifestyle together?