How to create a concensual dialect for multiple people?

I'm currently creating a fictional language for a story I'm writing. I want to bring in that language in the real world so I can express myself in this language. I'm also planning to use this language for a presentation I have to do in my university. I want to encourage my friends to use this language too. I want my friends to know this language so they can guess what I'm saying and start a conversation with me. So instead of creating a language I want to create a dialect. I want to create a dialect that everyone agrees with. I completely understand if my friends have different preferences, so I need a way for us to be on the same page. So they can change the dialect in a way that everyone agrees with. So I'm here to ask the following questions <br>1. How to create a dialect that everyone agrees with?<br>2. What are the best dialects for a group of people to concursively agree with?<br>3. How can we make this dialect well known to everyone in the group?