A lot of race-day stress is logistics. The corral, the bib, the bag, and the person waiting at mile 8 all have a simple version that works, and a complicated version that does not.
Start in the right corral
Line up with the pace you expect to run, not the corral in front of it. An optimistic predicted time puts you ahead of people who belong there and makes the first mile a weave. Enter the time you can actually hold. The race-day glossary covers gun time versus chip time if the results page is the confusing part.
Pin the bib on the shirt you will start in
If the chip is in the bib, do not fold it, trim it, or leave it in the hotel. Pin it flat on the front. A belt can work only if that race allows it. Check the race site, not a different event's rules.
Drop bags
A drop bag is for after the finish, or for a gear check the race actually offers. It is not a place for the gel you need at mile 1. Put nothing in it that you need before the start. Label it with the bib number the race asks for.
One meeting point
Tell family one spot after a turn they can walk to, plus a backup if the corral street is closed. Do not rely on them for a bottle or a gel unless you have practiced that handoff. A text at the start and at the finish is enough. Mid-race messages get missed.