People always act out of self-interest. Motivations are feelings that make us do something. This means that they are automatic similar to going to the restroom or having to reply back to an urgent text message.
People have the following needs:
Physiological – To avoid death and pain, to breathe, to drink, to eat food and sleep
Familial – To be loved, protected, and to have status/respect/justice
Self-Actualization – To reach our potential and to understand how the world works
When selling, try your best to be enthusiastic and repeat your main ideas.
However, remember that enthusiasm is not the same at fanaticism and you need to convince someone that your idea or product is useful in his life.
Generally the hardest part is starting the conversation. Remember the easiest way to start a conversation is to just be interested in the other person’s interests, give your thoughts on an issue, and then to ask questions.
Facts are important but the feelings that come from the facts are more important since humans are both rational and emotional creatures.
Avoid manipulation and guilt-tripping unless you really have to. Remember that rejection is going to happen and persuasion is more of an art than a science. This means that you have to be creative and just keep trying.