I promote bitcoin to my friends and relatives by showing them what i earn. And by teaching them all my knowledge about bitcoin. And i tell them to share it also to other people.
Its not easy to encourage people to invest on bitcoin, so many ways to promote but people will not easily believe on what you say. I usually share not just my knowledge but also some of my transactions with bitcoin. We must not stop to promote bitcoin, lets start with our family, friends and other relatives and keep your goal to help many people.