I was in for my appointment at the US embassy in London today. I thought it would be useful to share my experience.
My appointment was at 8am. I arrived around 7:30am to be faced with sizeable queues. There are three queues that I could see. 1 on the left hand side for us citizens. 2 on the right. One of those to check in after which you would join the other longer queue. As you have an appointment you can go straight to the front of the check in queue. Make sure and have your ds-260 confirmation printed to show along with your passport.
Security step is next. I had a small back pack, bottle of water, phone, keys, wallet and documents. I just had to open the water bottle to take a sip I guess to show it was nothing dodgy.
Then walked through the courtyard and into building where there is another queue. This one is to get your ticket number.
After this take the elevator to the first floor. Once there I was directed to sit in the main area but soon noticed that I should've been round the corner. Left out the elevator then left again to the very end. There are instructions on the ticket.
I was in the first few appointments of the day and was seen around 8:02. This initial counter visit was to take my docs. Passport, birth certificate, marriage certificate, police record and passport photo along with my biometrics. Was asked when I planned to move to the US. Was asked for my confirmation that I had set up passport delivery. I didn't have this but confirmed that I had done it. Was then told to sit down again.
Was called up again around 8:30. Confirmed my name, date of birth, asked how and when I met my partner, what she does for a living, where in the US she lives, does she or I have any children or previous marriages then that was that. Congratulated me, returned my docs and told me the passport would be sent in 3-5 days. Was out of there by 8:40am.
All in all it was really straightforward and both people I spoke to were friendly.
Delighted this is finally coming to an end. Good luck to everyone else on the journey.