I generally will check the scope with a bore scope or laser if I have it with me. Then I will shoot @25yds to see where it is - esp left/rigth. Then a shot at 50 and them to 100 nd then to longer distance if desired.. When I hunted a lot out west I sighted zero at 300 yds ....Depends on how far off from zero it is. I like to start with my laser bore sighter, just to get it on paper (but I've had a couple that the bore sighter ended up being dead nuts on). Usually only takes a few after that, but I always do three shot groups whenever I zero a scope.
If you have a lead sled or some such that won't move, you can try the "one shot" method. I've never tried it, but know a couple people that have.