I think I'm going to re-do mine this weekend, not sure I put enough grease on the right parts tbh, the creaking noise has come back albeit reduced in frequency.This ^^^^ Make sure you give it a good clean, and grease it up. That was a regular issue on my fixed at first - never returned now.
What I'd do is remove bars and stem, remove spacers, top cap, compression ring. Drop out forks and remove bearings. Wipe all surfaces clean, regrease, bearings woun't need much attion if smooth, but clean the outer surface, slap grease on it and re assemble. Clean and re-grease bar/stem interface and steerer.
Wasn't sure exactly which parts to grease so didn't want to overdo it.
Is there a pic somewhere of the exact parts/places to grease?