measure true erd correctly. measure twice, buy spokes once.
measure flange diameter and offsets correctly too.
dont trust any published measurements from any maker.
get welded rims, not pinned or sleeved!
get rims with eyelets, these crack less around the spoke holes.
get 32 spokes.
get dt 2,0-1,8-2,0 spokes (or sapim)
get brass nipples.
dont use locking compound, use grease for seats and in/on threads to prevent windup and allow for eventual future adjustment.
do all stress relieving methods during the build

done.

will last a long time.

use these guides here
https://www.wheelpro.co.uk/spokecalc/ (also click the texts for explanation)
Wheels
Wheelbuilding