What I do at gigs is scribble my notes and feelings of the band, the performance, the gig in my wee notebook, then hours/days later, I just type up exactly what I've written, sometimes adding more detail, often adding links and photos where I can. I don't think back and try to remember what the gig was like, I just copy the reatime notes.
So by this stage of the festival I'm so drunk I can barely hold my pen. I'd just finished my bottle of rum, and what I wrote for the review in my notebook was this:-
Write about Rachel later
Then at this point I lurched out of the diesel shed into the buffet wagon, verbally abused my friends, then staggered off the festivals site and threw up in my car.