Yeah what @rvogt said, but I’ll add that you can use a corner jig and a compound jig like he describes to great effect.
You’d design and cut your jig to position however many items you can do at once, then you seat that into a corner that you cut out of throwaway material like cardboard.
So if you wanted to come back and do more of those items the next day, you simply cut a quick corner for registration, then slide the jig you cut the day before into place, and you’ll know exactly where it is, to within a kerf.
If that’s not accurate enough, you can kerf correct your corner jig and get within about 0.002" without much effort. If accuracy of that caliber is required definitely look into crumb tray boots, to keep the tray from wiggling.
For an example of a corner jig in action (minus the compound jig that would slot into it):