Hmm this is interesting to think about seeing as hills are pretty much a speciality of mine (5"10, 10 stone..) Thinking about my approach to climbing, the first obvious but unhelpful tip is:
slow right down, change to my bottom gear and go very slowly
Like my experience when climbing is of a continual engagement with "how hard do I need to 'attack' this to keep up forward momentum". This is something I developed from riding on fixed: you become hyper-aware of increases in gradient, knowing "when I get to that bit 5 yards ahead I'm going to have to up the levels": it's a process of gauging your reserves and what effort is needed to keep the gear turning. So - maybe give "rolling" terrain a go on fixed - in my experience 72" will get you over anything that's not either a mountain or a potential hill-climb course. This will force you to 'htfu' and hopefully get you out of the above-quoted habit.
Then the idea would be when geared you see the hill as an obstacle to be defeated by applying increased effort to rather than bailing out and notching down through the gears. At the risk of contradicting myself, I wouldn't recommend over-geared climbing when you have the option of gears (at least for climbing training rather than e.g. for strength training): it just makes the bike/your legs feel inefficient and reinforces the "hills are difficult" mentality, whereas once you've been up some steep stuff fixed you'd want to feel like gears/the option of maintaining your preferred/optimal cadence is an extra boost to your effort.
Then in my admittedly limited experience climbing geared, that gauging of the upcoming steepness of the hill is replaced by "what cadence feels like I'm putting out my best effort". I suppose this is something like "let the hill come to you": keep putting out an optimal sustainable effort and use the change of ratios to even out changes in gradient. Weirdly for me this means I now don't notice when the hill gets steeper - I've got to the top of some stuff that would be do-or-die on 72" without noticing anything extreme about it - it was just a matter of "this [remaining] distance at this effort"
Don't know if this is helpful or not; I'm one of those people who like hills, to me they're a satisfying challenge to try and defeat with the maximum panache, rather than an interminable slog