Relationship is a romantic or sexual involvement between two persons.
Keeping a healthy relationship is not that easy. Even if there are 100 steps written here, trust me it won't work 100%. Because human differs, likewise our thinking and reasoning. It just depends on the people involved.
Some of the steps below can help.
First and foremost is to study the person, its really difficult though, but this is the most tolerating part of the relationship. Just as we study some lecturers and their courses so as not to fall into their nest or fail. Relationship demands it too, if we really want to be with that person. We can study a persons character, strength, weakness, likes and dislikes, best mood, food, hobbies, favorite stuffs etc.
After studying comes understanding. Believe me, some people are too difficult to understand. Complicating their lifestyle and making the entire relationship difficult to handle. But we must still strive to give in our best. We must also make ourselves understandable before trying to study and understand someone else.
Avoid anything that could lead to hurting each other. It usually happens after studying and understanding the person. Try as much as you can not to use the persons weakness to hurt him/her. It really hurts like hell.
Trust is like a paper, once its crumpled it can't be perfect again. Lead a trustworthy life and also make the person know you trust him/her. Avoid doubt, fear and insecurity.
Surly anger must arise some day, but dare not to allow it control you. Sometimes before stirring up anger, imagine if you won't do the same if you're in the other persons shoe.
Be slow to anger and be quick to forgive.
This is one thing people wants so much in relationships. Everybody wants attention. Give attention, as much as you can to your partner. But not at your own detriment or expense of work. Because if you're fired, attention won't pay the bills.
Love your partner as you love yourself. Love is not built on emotional feelings or sympathie, but actions. Attend to her needs and don't wait until she demands for it. Some are very shy to do such and expects you to understand. Likewise the other person, its vice versa. Surprise each other with gifts, admiration, compliments and say how much you love and cherish each other. Love and care works together because showing love eventually shows that you care.
Avoid gossiping each other with friends. If there should be a third party in the relationship, it should be a trusted and God fearing person. Gossips creates room for rumors and rumors bridges trust.
As time goes on there are more things to discover which can really keep the relationship in a healthy state and to the next level.
It all depends on commitment. For the main time I hope this will help.