You’re generally qualified, on time, and well-dressed. You asked some questions in the job interview, and it ended with a “we’ll definitely be in touch”….but you didn’t get the job!
Next time you want to really get that interviewer (or anyone) on your side, try mirroring that person. If they sit ramrod straight, so do you. If they blink a lot, so do you. If they talk really fast, so do you. If they cross their legs, recline, and rest their chin on their fist, so do you. Get it?
You can be pretty blatant without the other person catching on, but it’s better to be subtle about it.
Sounds silly, works like magic. When you leave, the other person will have a memorable impression of you. There will be something about you that was different from the rest, something about you they liked. All other things being equal, a little harmless mirroring can tip the scales in your favor.