Go to the site, walk around it, take it in, take your time, find a vantage point then, without closing your eyes, stare hard and imagine it as was. Imagine as hard as you can.
I find this a perfectly satifactory way to dea with ruined sites, ever since I mentally re-erected the Grand Menhir Brise in Locmariaquer.
My wife thinks I can see ghosts too, but to be honest its just a good imagination.