This look can be dressed down or dressed up. Rather than wearing the tartan/flannel shirt buttoned up or draped over your shoulders, instead tie it around your waist for a grunge chic look. Rock with a pair of beaten Doc Marten boots and heavy eyeliner. A golden chain or large statement ring with give an urban twist to your outfit. Again, keep the top simple by wearing a plain white crop. A tote bag is also perfect when out in the city as it's light, hard for people to pick pocket from (if it's deep enough of course) and can fit tons of stuff inside without breaking!
Makeup and Beauty:
Make sure your skin stays well hydrated, moisturized and oil free when spending the day out in the city. There may be fumes and pollution your skin isn't use to so extra protection is needed! A light foundation will stop you from feeling 'caked up' and a simple set powder will prevent an un-wanted oily nose. I would suggest using Imperialis Moisturiser by Lush Cosmetics (£12/.75) to help fight off any bacteria your skin can pick up.
Keep your hair SIMPLE. Wearing it up in a messy bun looks casual yet screams catwalk at the same time. To get the look, tie your hair up in a bun then thread out a few hairs to give it the messy look. use plenty of bobby pins and hairspray to maintain it throughout the day!
Finally, if you are going to explore any major cities or need to block out the sound of busy commuters, make sure you have the perfect soundtrack. Personally, I found listening to The 1975 really helps me to emerge myself into London's busy atmosphere without it being too much.