If you want the segment to be useful to others, try to start it and stop it at points that don't require "luck". For example, instead of starting a segment just before a stop, or right at a stop, start it 25 feet beyond the stop. That way it doesn't matter that much whether you had to stop or not prior to the segment. Same for ending the segment. Don't end it right at a stop sign or stop light; end it 25 feet or so before, so that anyone has adequate time to safely come to a stop.
Also, Strava will suggest a similar segment to yours, if it exists. If there are insignificant differences, go with the segment that's already there, or make your segment private.