How do you get an stranger interested in an unknown topic?

Topic- How do you get an stranger interested in an unknown topic?
E.Q.- What is the best in becoming a Muay Thai Fighter?

Objective- The skills and information that are going to be taught in my presentation are persuasive skills to keep a person interested on something unknown and keep the person interested through a long period of time.
Lesson plan-  1) Hook beginning of presentation; What is an appropriate way to catch an strangers attention with out freaking them out and wanting to keep talking to you? End of presentation; How would you approach an stranger if you want to sell them a product?
2) Low velocity; I'll teach the audience what how people listen to things you want to sell. How to go ride to the point without losing the consumers attention and how to sell the product.
3) Medium; I'll teach them how to sell a Muay Thai membership. Is similar as selling gym memberships.
4) High; I'll teach them why is necessary to known how to engage with strangers and how it will help them in the future.
Activity- The students will be in groups, then they'll be responsible of making a poster promoting a product and being able to catch people attentions.
Materials- Posters and colors