1. Honesty. Honesty is a quality that every good friend will have. Notice how I did not say "brutal honesty." A good friend will be able to tell you things how they are without totally destroying your confidence and friendship. They can be honest with you about how you dress, your health, and even who you date. And because they are honest you will value their friendship even more and the relationship will be stronger because of it.
2. Loyalty. Loyalty is a quality that every true friend should and will most definitely have. This however is not a quality that they will have to work at. Loyalty comes naturally when you are a good friend or when you find a good friend. A good friend will be loyal even when things get sticky or they don't really agree with your decision. They will stick by your side because they love you as a friend and will try and be supportive no matter what. This however will not condone them to behave the same way you are behaving.
3. Trustworthy. There's nothing worse than someone you think you're friends with but you can't trust worth a darn. That my friend is not someone who you would consider to be a good friend. Being trustworthy is a trait that every good friend should have. If you can't trust them then it will be impossible to form a relationship with them. And vice versa. You must also be trustworthy if you want to be a good friend. No one likes to hang out with the guy or girl that can't keep their mouth shut about anything.
4. Sense of Humor. Not everyone will have the same sense of humor so depending on your personality type will depend on your sense of humor. Being able to laugh at themselves and joke around about dumb things will definitely make anyone likable. The secret is finding the balance. A friend who is constantly telling jokes about themselves and others is no fun to be around; friends who are too sarcastic about things get old. So finding someone with a good sense of humor and balance is important.
5. A good listener. There are more people out there today that are willing to give out all the advice they can think of but not very many who will just sit and listen to what you are saying. Being a good listener is a rare quality to find in a good friend but can also be learned. Being able to listen to someone's life problems without piping in is a quality that anyone should be glad to have themselves or be glad to find in a friend.
6. Dependable. Dependability is always a good trait to have whether you work on it yourself or whether you're looking for it in a friend. Finding someone who is dependable and will follow through with things they promise to do is hard to find these days.

Of course finding qualities of a good friend are somewhat relative and will depend on the person and their personality. These qualities are fairly universal however and if you can find a friend with just a few of these traits you can deem yourself lucky.