Looks like a few people have already offered up some good suggestions. I think your own trial and error is the most rewarding pathway to lightening up. Take detailed notes on everything you bring, the quantity of each item you use, things you didn't use, etc. I don't usually document anything while I'm out on a trip, but I make a mental note when out there, then write things down when I get back. This process helps me lighten my load, pack differently next time, and be more efficient on future trips.
Have fun out there!! The Sierras are on my list for next year.