I use smart water bottles and will never go back to having a water bladder.
If there's no snow, trail runners are amazing, weight on your feet can be as important as weight on your back.
I upgraded to the katadyn befree water filter. Not sure if that counts as a weight savings, it depends on your current setup.
Then I suppose you want to look at the big three: tent, sleep system, backpack. Try to get the combination of all three to under 6 pounds and you'll have a good start. (Big agnes Flycreek UL is a great tent for example)
Food can be a big one on long trips. Calculate calories per ounce, be wise about what food you bring.
How much water you carry will make a significant difference. Research your trail, bring a little extra water to make it to the next spot, and when you resupply water, make sure you drink right there, so you don't have to carry as much on your shoulders
Research DIY ultralight solutions if you're operating on a budget.
Like for stoves, a quick search on the web for 'penny stove' can open you to a whole world of people trying to optimize homemade ultralight stoves.
One other thing I found after years of using an old self-inflating sleeping pad was that they make blow-to-inflate pads that are much lighter and more durable now that they used to.
If you can adapt to them and have convenient mounting supports (e.g. trees,) hammock tents are an option that can be lighter than tent+pad. Definitely not for everyone, though.
My own personal backpack for weekend trips is a very small volume suspended-mesh model. It's the lightest thing I could find with a robust suspension. I strap my tent, at least, and whatever else is needful to the outside of the pack, and it works for me!
Easily my biggest weight and space savings came when I moved from using a tent to a hammock and rainfly. It paired great with my Big Agnes bag where the pad slips into the bottom, keeping the pad below me while I toss and turn.