Stella will spawn and stay in that location, so you don't have to worry about her moving should you use Zoom.
(Before getting to the steps though, a big tip: hunt for Stella at night time in game! It will be much easier to see her due to the colored glow/aura she has!) Now that you know WHERE Stella appears, it's time to discuss HOW you can find her and what you should do. Of the locations, #1 and #5 are the easiest to spot her, with #4 being the most difficult. She will be floating around the top of the hill. This can be the hardest spot to find her, so head toward the southwest dead end and look around trees.
I have most everything I wanted to include, but some details will need expanded on via an edit, such as expanding on "The Spoils," section. Please Note: Some details of the guide are subject to change. With all the new features and additions added to Dragon Quest VIII's 3DS release, there's one that was a real flapping surprise: Stella from Dragon Quest IX: Sentinels of the Starry Skies! This guide will help you in the hunt for Stella in Dragon Quest VIII: Journey of the Cursed King for Nintendo 3DS. Thanks to YangustheLegendaryBandit on the Forums for this guide.