Its the city. Unless you know someone in the area no one pays any attention unless you bring it to yourself. Don't act nervous or out of sorts or too rushed. Dress decent...not too good and not too bad. Wear neutral colors that don't attract attention. be well groomed. Its literally expected of people to wear masks in public now. During the day you could wear shades. You'll only stand out if you look overdressed or under dressed for the area. Average looking guys don't attract attention or warrant notice. If its an issue of standing outside a door waiting.....make an appointment and then call and inform them you are there. Most places will be ready to answer and let you in right away.
I'd be more concerned with semi-residential....some neighbors watch everything, especially old people. For those park a couple blocks away and walk in. The first place I ever went I parked my car outside the AMP and then walked down the street a few blocks for a coffee then once I finished the coffee I walked back so there was a disconnect with me and my car as I entered the building. It made me feel more comfortable but wasn't necessary.
I totally agree. In Center City Philly, no one really cares who you are, where you are going and for why. Just act natural as if you are visiting a friend or dropping off something to an associate. If you are in a residential area, I would be more cautious and I like the suggestion about the disconnect between your parked car and you. Just don't stress out and enjoy.