Communication
Communication is extremely important. It is arguably the most obvious component of a healthy relationship, but it is also the least practiced component. We all know that communication is key, but many people still refuse to communicate with their partners. This is often due to the fact that we create our own stories in our heads that we choose to believe over reality.
We justify these stories in our heads and make sense of a good or bad situation even if things can still be made more clear. People tell themselves their partner may not want something, they might get mad at something you say or do, they even might stop talking to you altogether. However, we need to simply realize that none of us are mindreaders (unless you are, then you can skip this part I suppose) and things need to be said.
Letting someone know you appreciate them or that you are proud of them is just as important as letting them know your concerns and things that upset you.
Another big part of communication that we all tend to overlook is simply asking questions. In the event that your partner has not yet mastered coming forth with their thoughts, just asking them questions about their feelings will help in bettering your relationship.
Patience
Patience should always be thought of in regards to yourself as well as your partner.
Being patient with your partner is clearly very important. If your partner is trying to do anything himself/herself, they typically are going to need you to be supportive rather than pretend to be their aggressive parent. The same goes for changes you might be going through; give your partner some time to adjust to new things going on with you. Even in an argument, allow your partner time to cool down, time to speak their mind, or even time to just be upset.
One of the worst moves in any relationship is not accepting someone's feelings or acting as if they are not warranted. This isn't to say that you should let people scream at you because of a forgotten grocery item at the store, but you should definitely be understanding when the situation calls for it.
This goes for you as well; be patient with yourself. If you are the one upset about something, give yourself the time to calm down before going into a situation the wrong way. Also, be sure to allow yourself to make mistakes; if you beat yourself up about every single thing, you aren't allowing yourself to learn from them and grow!
Patience, patience, patience!
An Open Mind
This goes hand in hand with demonstrating patience, and it is arguably another seemingly obvious factor in a healthy relationship.
It's easy for people to become set in their ways and continue along one path simply because it's the path they're most familiar with. Relationships, on the other hand, should be forever changing, forever growing. People are not static, so a relationship between two people should not be static either.
As we've all heard many times before, try putting yourself in their shoes, it will do wonders for your relationship. This will lessen the number of snap judgments (or judgments in general) that are made, allowing you and your partner to become more comfortable and honest with one another.