The words "I'm Sorry" shows that you are willing to admit that you are not perfect, and removes the power struggle from blaming each other.

"Please" shows that you are polite and not demanding or controlling.

"Thank you" shows that you are grateful for what you have, and appreciate your partner or friend.

These three words are powerful in any relationship. They show you are willing to work on yourself, and change your own faults, rather than blaming, manipulating, and judging others involved in your life.  You could call these words as a form of respect, because it shows consideration for the people in your relationships.  However, respect is a lot more complicated than just saying a few words.  Every person is unique, every personality is different, and as a result the "rules" of respect change.

Many people, equate love with respect subconsciously. Although I agree with respect being a part of a relationship, I don't necessarily believe it to be equal to love. Real love is  unconditional. It means that you are willing to love someone no matter how imperfect they are, and nothing they do or don't do will change that.  All people make mistakes, does that mean that they don't deserve love?  Love is a universal gift.  It is to be given freely, not earned. 

Respect is a whole different story.  It is of the ego, and is something that has to be earned by giving it.  It helps relationships run smoothly, because then both people feel valued, but this does not determine the level of love that each person has for the other. 

First and foremost, take care of your body, your surroundings, your responsibilities, and the things you own.  People have a hard time respecting you if you don't respect yourself, especially if they live or work with you on a daily basis. 

Secondly, respect is earned by giving it.  This is a hard thing for people to understand.  Why should I respect others first?  Put yourself in the other person's shoes.  They are probably thinking the same thing!  So it has to start somewhere.  The best way to do this is to follow "The Golden Rule".  "Do unto others as ye would have them do unto you".  Be considerate of other people's boundaries.  Ask before acting.  Always remember that everyone has different boundaries than you will, so take extra steps not to cross them.    

Humans are not perfect.  You will eventually make a mistake and say something or do something that might make the other feel disrespected.  However, this is where a genuine "I'm Sorry" comes in handy!  Make sure to make amends and resolve the issue.  If not resentment will build and then respect will be crushed under the pressure. 

Most of these mistakes can be avoided if you make sure to find out what boundaries someone has by asking them.  Communication is very important, and it saves a lot of stress in this department.