Always have an escape plan. Period.
An urban environment is dangerous, tricky and unpredictable. Things happen fast, often without warning.
Always have a plan. Be ready. However, always have a backup plan, because the plan probably won’t work, that's the nature of the beast. Yet, Rule 1 states: Always have an escape plan. You know all the rest of the plans will fail at some point, so be prepared.
A simple tshirt, stating the most important rule. Urban grey and black text.
When in doubt, Red Team it.
Get it here and help spread the word.