Here are some of the things I do myself and some advice I guess you could use, but at the same time it's kinda hard to tell, some of the things I do became so natural to me I even don't realize it anymore, I only notice it when I see other hikers with much heavier options:
I carry a poncho tarp, which is convenient for both rain and as a shelter.
Stakes with a cross form are light and tough.
A headlamp is well enough as a flashlight, you can hold it in your hand too.
You barely need a knife, a small folder is enough.
You don't need hot water to cook, there are plenty things that can be kept for a long time and don't require water, like oil bread, muesli, honey, dry cheese, dry sausage or dry ham, plus semolina and lentils can be cooked with only cold water. That can save you the weight of a stove.
Ziploc bags are great to organize stuff while keeping it all waterproof, and light.
Trash bags make great and light bag waterproofers.
Marseille, Alep and Castille soap are very concentrated (from most to least), and will last you a long time.
Microfiber towels are great, microfiber mops are the same thing and much cheaper, and often much better.
Plastic bottles are the lightest bottles you can get and all you need.
Otherwise I only bring the bare minimum:
Bag
Headlamp
Knife
Lighter
Map+compass
Mirror+whistle
Bottle of water+cloth filter+purification tabs
Soap+Towel
Toothbrush+toothpaste
Toilet paper
Ponchotarp+stakes
Groundcloth+sleeping map+bag
Appropriate clothing
There are plenty more things I can't think of, but still it's not only about paying more for lighter gear, though it's inevitable for things like bag or sleeping bag, but there are plenty lightweight alternatives are actually much cheaper than the heavier ones. It's about only carrying what you need along with plenty little tips to make your gear more versatile.
Check this guy too, he has some pretty good tips and an impressive setup for the AT:
http://www.adventurealan.com/ 
