Don't dismiss Mike Clelland so easily! Granted, leaving TP at home might be an uncomfortable and needless way to save a few grams, but his idea for water bottles exemplifies to me the very zen of UL backpacking:
Granted, it doesn't save much weight, but the idea forces you to think about the weight of everything
in your pack.
You can go UL without sacrificing comfort, safety, or Leave No Trace principles. Here's a few hints that I've found most useful.
1. Decide if you're a hiker or a camper, or something else
. One is not better than the other. I've found I like to cover long distances each day and UL gear and strategies help me do that. But if you just want to do 7 km a day and then camp, nap, take photos, fish, or read, it's your trip and that's your decision.
2. Buy a digital 5 kg scale and weigh everything.
Everything (except "nothing") weighs something, and it all adds up. Consider setting up a spreadsheet with all your gear weights. Don't even trust retailer's stated weights.
3. Adopt, or at least strive for, the Scandinavian 343 method.
That is, your three heaviest items - shelter, sleep system, and pack - should weigh no more that 3 kilos combined. Once you've trimmed those weights, you can think about cutting down your toothbrush.
I used to carry an MEC Gothic Arch tent (+/- 3 kg), a Feathered Friends Goretex bag good to -7*C and a shorty Thermarest (1.6 kg), and a Serratus 65 litre pack (+/- 1.5 kg). Total weight about 6 kg. Great pieces of gear but overkill for summer backpacking.
I now carry a 900 g Tarptent Moment, a 500 g quilt good to 0*C, a super-comfy 456g Exped Synmat UL, and a 635 g SMD Swift pack. Total weight about 2.6 kg with no loss of comfort or practicality. My tent is definitely smaller and less resistant to alpine winter storms that the Gothic Arch, but it's proven itself perfectly adequate for anything summer solo trips may throw at it. And it pitches in under 2 minutes.
Last summer I double-hiked the Skyline Trail from Maligne L. to Signal Camp in 1 1/4 days and back the next day. This is a short 45 km hike, but I saw numerous hikers labouring under packs as large as I've carried on mountaineering expeditions to Alaska or the Yukon. I felt no smug sense of schadenfreude
and I thought I was as well-prepared as they were.
4. Download this free UL backpacking ebook.
Glean whatever you can from it.