What most naturally follows?

How to be green in the city
Bring your own bag to the market, convenience store, hardware store, everywhere.
Get ones reusable bags that fold up easily into a pouch so you can throw it in your purse or backpack and always have one with you.
Bring your own cup.
Use that mug as much as you can. Fast food places like mcdonald's might not be as open but subway usually is fine with it.