It was never my intention to focus on the Guardian badge in Ingress. Earning it seemed at lot more about how other agents play instead of about how you play. But around day 100 you start to get the itch that this portal might be the one that makes it all the way. Mine finally did.
Not sure if any strategy is actually key to earning the Guardian badge. I think it’s mostly luck. But I can tell you how I handled mine and maybe that will help you with problems you’re encountering.
Low Resonator Count
One resonator is all you need to own a portal. Further resonators will only draw more attention to it, and if there’s anything you don’t want, it’s attention. Put one L8 resonator on your portal and leave it be. This means it’s less likely to be see on the Intel map, and no one will accidentally make a field with it as an anchor.
Since you can’t rely on any backup resonators, you’ll want to recharge frequently. While I didn’t see myself as focusing on the Guardian badge, I have been working on my Recharger badge so this goes hand in hand. Make your guardian candidates your first recharge then carry on with any other recharging strategy you have. Learn to quickly find their portal keys when sorted by Name (since your distance will change.) Daily recharging isn’t necessary, but is ideal.
You may find that other agents have ‘bumped’ your portal, adding their own resonators to fill in your gaps. I never recharged their resonators, so that within a week mine was on the only one there.
Have you heard of this rule? It says “Don’t Be a Dick.” A lot of Guardian candidates are lost because player A does something player B doesn’t like, so player B makes a point to hunt down player A’s portals. I avoided doing anything anyone wouldn’t like by not playing much in the past few months — that’s not really a great strategy for enjoying a game. But I think you can follow the same principle by focusing on fielding, missions, and meetups when you have a strong Guardian candidate.
Hunting for unique portals by playing on a side of town you don’t normally visit can be seen as crude by an agent who’s already mad, even though you’re playing with good intent. Normally I wouldn’t let something like that bother me, and I’d just play where I wanted anyway. But I’d rather avoid the conflict entirely if it keeps my 100+ day Guardian alive. No conflicts means stable portals.
My Guardian was actually a pair of portals right next to each other. They both made it. However a couple times it was a close call. Never were my portals directly attacked, but they both took heavy damage from incidental XMPs nearby. Also, a couple of times one of my portals anchored a relatively large field — but not both. It never ended up being the clincher for me, but it was a nice insurance to have two portals instead of one.