Set your bike up in a stable position where you can work on it comfortably.
Use metal zip ties to affix the heavy battery holder as close to the wheel’s hub as possible. If your hub is wide enough, you could even attach the battery pack directly to it.
Use plastic zip ties to attach the LED strip and Pro Trinket (as well as any switch or sensor you may have optionally added) to the spokes of the wheel.
In this particular wheel, the mode selector switch is attached with sticky foam tape to a neighboring spoke.
Night photos and video for gifs by Andrew Baker.