Clean the rim with soapy water, gently scrub it with a scotch brite pad, then, warm up the rim by either leaving it in the sun for a few minutes, or using a blow dryer/heat gun. This does the trick for me, and the tape tends to stay adhered for longer. Good luck
Have you tried warming the rim / tape before applying it? I’ve used Tesa / WTB tape which is the same as Stan’s I think. It’s less sticky than the DT Swiss tape I’ve normally used but I’ve always got it to stick. I normally use a hairdryer to warm it up and do it in the house rather than a cold garage. I think the tip to put a tyre on with inner tube in could work to help stick it down but I’ve never had to resort to it. But then I’ve never had carbon rims - it’s always been alloy - used DT Swiss / wtb / Alex rims.
Scotchbrite pad scuff up, wipe down, tape it, then let it sit with a tube installed for a day. Gorilla tape is a nightmare.
This. I had endless trouble getting tape to stick with a brand new DT EX511 rim. I cleaned it with alcohol, acetone, brake cleaner, heated it, and it still wouldn't stick.
Finally I roughed the surface with 400 grit sandpaper, cleaned with alcohol, then warmed lightly with a heat gun and it stuck great.
Op is talking about CARBON rims. For posterity, DO NOT use abrasives on carbon rims!
You don't need the tape to stick to the rim extremely well, you need the tape to stick to the tape well where it overlaps, which most purposeful rim tape sucks at especially when disturbed by tire beads and levers pushing it around. Keep your thumb on the tape end to hold it still as you work your way around the rim with good tension, then overlap by at least 4".
Unless you have a habit of popping your tires off to show other riders your sick rim channel layup, leaving ugly adhesive behind, assuming you even need to ever retape is GOOD as that will help your next roll get purchase and stick even better (think tubs). Most of us set it and forget it for years/the life of the rim and never have to worry about this of course.