This information is from an eharmony article. (I’m going to paraphrase in order to shorten this up a bit.)

1) You’re Not Chasing the Relationship’s Potential. The basic idea is that you’re not waiting for something to happen in order for you to be happy in the relationship. For example, hoping the person will get over some habit. Feeling that the person would be nicer if he/she could just get through a bad phase at work.

2) Who You Are Is Good Enough. You’re perfect just the way you are. You’re not trying to change the way you are or what you look like in order to please the other person. You know the person is happy with you and that changes aren’t necessary. (Personal development is different. If you want to make changes and improvements for yourself, that’s a different story.)

3) You Manage Conflict Well. The example they give in the article is about couple A who fights and couple B who never fight. They say that couple A is more likely to go the distance because they’re able to get their needs met. Couple B isn’t being forthcoming with their feelings and emotions. The important thing to remember is that fighting isn’t necessarily a bad thing. Fighting isn’t fun or pleasant but it shouldn’t be hurtful or verbally abusive. There are two people in a relationship. They’re not going to agree on everything. Make sure that when they’re is conflict that you are respectful towards each other and that it’s healthy. How you fight in a relationship is very important. If your partner always goes for the jugular (so to speak), cut your losses now.

4) The Mundane Is Suddenly Interesting. The mundane is suddenly interesting. You want to know all sorts of details about the person your with such as things about his/her childhood. You want to see childhood pictures, etc. If you’re genuinely interested in the person’s life, that’s a very good sign.

5) There’s Minimal Drama—or None at All. When you do fight, you do your best to fight fair. You admit when you’re wrong, you listen to each other, you acknowledge one another’s good points, and you apologize when you cross lines. If you two are dealing with constant drama, where one of you is trying to create high emotions to manipulate the other or there’s constant turbulence without some sort of resolution, then be careful about fully committing to the relationship at this point. High drama is a definite red flag when it comes to long-term relationship success.

6) Your Friends and Family See What You See. They like the person you’re with. They encourage the relationship. If the people you’re close with don’t like the person or they think the person is wrong for you, you should listen.

7) You Know How to Make Them Happy Do you know what it takes to makes your significant other happy? Think about minor, moment-by-moment issues, like where that person likes to eat and what kind of back rub he or she enjoys. Do you know how to help her relieve stress? Can you get her to talk about her dreams and visions for the future? When she’s struggling at work or with a family issue, can you help her come through the storm and find the sun again? And, just as important, does your partner know how to do this for you as well? If so, that’s another reason to believe that you’ve found “The One.”

You Have the Same Life Priorities. Opposites may attract, but they rarely make for a good long-term relationship. Compatibility really is key when it comes to creating a deep and lasting connection between two people.

For example, if you want to begin preparing for the future and building toward certain life and career goals, but your partner mainly wants to make enough money so that he or she can party this weekend, then you two are probably working with fairly different priorities. I also want to include with this one the idea of doing things at the same pace as your partner. If you like to stay in, curl up on the couch, and have calm evenings in and your partner likes to go out drinking and going to bars, then you’re very different types of people and the relationship will never work long-term.

And the opposite it is true, too: If your priorities match up well, then you two have a much better chance of long-term happiness and fulfillment together.

9) You Respect the Person Deeply. Mutual respect has to be there. You must honor each other’s feelings, emotions, and needs. Respect is extremely important in order for any relationship to thrive.