The following are the steps to a healthy relationship:

1. Show consideration. If you are considerate of one another's needs, wants, desires, and wishes there will be far less to fight about, and thus far happier times. Often, it is simply a lack of consideration that leads to fights, problems and criticisms in a relationship, which in turn leads to unhappiness.
2. Work on yourself not others. If you want to be in a healthy relationship you need to focus on the things you could do to improve, not the things your spouse, friends, or whomever you are in a relationship with should improve on. You will never be happy if you are worried about what someone else can do better, instead of what you can do better.
3. Cooperate with one another. If you want to have a healthy relationship you have to have some give and some take. No one is going to agree all of the time, and hopefully you don't disagree all of the time, but the fact is cooperation is key to success in any relationship, whether a love relationship, a platonic friendship, or a work relationship.
4. Communication. Be it in any relationship, the most common complaints today about unhappiness is the lack of effective communication. It is when you want something and say another, or do not get your message across clearly. Whether it is a formal relationship between a boss and subordinates or a marriage, communication flaws leads to unhappiness. If there is a gap between the actual idea and the message sent across, or people are not listening and trying to understand, a relationship will be unhappy.
5. Trust. What is a healthy relationship without trust? If you want to be happy in a relationship you need to make sure that you have a high level of trust. Otherwise, how can you express feelings, hopes, desires, wishes, etc. with someone?
6. Respect. No matter what kind of relationship you have, it is not going to be healthy or happy if respect is not one of the key elements of it. So, respect one another, and show your respect for one another.
7. Appreciation. Gratitude goes a long way in healing hearts, making people feel loved, and in simply being happy. When you feel appreciated you try harder. When you show appreciation you are communicating to the person that you respect them, love them (possibly), and that the relationship matters to you.
8. Unconditional love. When you place conditions on your love for someone you are essentially telling them that they only matter to you if they hold up their end of the deal. This does not make for healthy of happy relationships.
9. Patience. It is important that you are very patient with people and situations in relationships. Sometimes you are running late because she took a while doing her hair, but it is not her fault that the streets are crowded, or that there is construction which means you have to take a length detour. So, remember these things and be patient in relationships.
10. Spend time together. If you want a healthy, happy relationship you always have to work at it, and one of the best ways to do that is to spend time with one another. If you only see each other in passing it is going to be hard to make your relationship better.