It is most common to put absent people at the end of the sentence:
Ich gehe mit einem Freund ins Kino.
In this context, people of a higher rank are mentioned before people of a lower rank, older people before younger people, and female people before male people. Some decades ago, the rule to put women at the beginning of the sentence had the highest priority, but that changed due to emancipation. This leads to:
Ich gehe mit meinem Chef, seiner Assistentin und einem Freund ins Kino.
The du comes always at first:
Morgen gehen du und ich ins Kino.
If you join all these rules, you end up with:
Du und ich gehen mit meinem Chef, seiner Assistentin und einem Freund ins Kino.
One more thing about the du: According to the actual styling rules, du is not capitalized anymore. An exception is when writing a personal letter: Then it is possible to capitalize the du, but it's not necessary.