With experience will come confidence in my opinion, but don't become sloppy with the other bits (like use a punting phone or sim, and try not to have anything on you that says who you are - if you do, then hide it as best you can....I usually only have car key, cash, punting phone).
Check the location on Google - hotels you can usually get a feel for lift/stair location, apartments and houses check out streetview to get a feel and check you are comfortable with it (I rule out many houses on this, apartments usually much easier to blend in as greater footfall).
I agree on not pacing the street - one quick check, then go somewhere else if early like a shop, coffee shop etc
But mainly is experience that counts - enables you to stroll up with confidence. Happy punting!