I recommend getting Ray Jadine's or Ryan Jordan's books on ultralight hiking. You should read through the gear lists and critiques here and compare them to your own.
Here are the basic concepts of ultralight hiking:
*Don't take anything that you won't use. About the only exception for me is first aid or other emergency/survival items--- stuff you never want to use but would be VERY glad to have when it hits the fan. And you can still keep those items Spartan and as light as possible. If it won't keep you warm, dry, fed, or safe, it stays home.
*Take only the amounts you need for the trip. Decanting soap, insect repellent, sunscreen and the like to small containers can save many ounces at little cost. You don't need a 3oz bottle of bug juice for an overnight trip, and so on.
*Weigh everything, write it down and add it up. Doing a spreadsheet may seem bothersome, but it is the easiest, cheapest way to lighten your kit. Scrutinize everything you put on your back. You will see the heavy stuff and know what to look for in future purchases to get your kit lighter and more coordinated (read efficient).
*Seek out the lightest, highest performance items you can afford. Sometimes that saves money: two recycled drinking water bottles will save you about 8oz and $20 over a pair of 1 liter Nalgene bottles. Chlorine dioxide tablets weigh far less than a filter, etc.
*Coordinate your gear to work as a finely tuned system rather than a random accumulation of gear that you just happen to like.
*Seek out items that can have multiple uses, like the rain cape/tarp shelter I mentioned above.
*Give up some of your city life conventions. You don't need separate sleeping clothes or several spare tee shirts, etc. It is okay to be a little smelly and dirty. It's not a fashion show and I don't care if your colors aren't coordinated.
*Know that you have control over what you take and how much it weighs. It is YOUR decision-- and also your responsibility to live with the outcome. Much of the excess that we pack is in response to fear of nature. Know how your body works. Understand the physics of staying warm and dry. Know how to navigate and take care of yourself. Your brain is (or should be) the best piece of equipment you have, and preparing it can make your wilderness experience safe and comfortable.
*Don't be afraid to hike your own hike. Everyone has opinions; they are free and worth every penny You will find opinions on both sides of the weight fence-- "that is too heavy" and "that is too fragile" for the same equipment. At one point my base weight was about 8 pounds, but I found frameless packs to be a royal pain to load and to wear, so I upped my kit weight a pound and I'm willing to live with the compromises. Many people need more comfortable sleeping pads, or warmer bag and clothing. What works for a 20 year old male in top condition may be different that your needs. I see no gain in suffering-- it is supposed to be recreation, not the Seal Team 6 training course! You may see gear lists that work for Colorado or the Sierra, but would be cold and wet in the PNW. For example, I like fleece and synthetic fills over down.
*Weight savings can snowball in your favor. A lighter kit allows you to use a lighter pack, you can wear lighter shoes, and so forth.
Of course there is a lot more to go in the pack and it adds up. If you have 20 items in your kit and can find replacements that are and average of 1oz lighter each, you saved 1.25 pounds. Cook kits tend to be too large and meal planning (or the lack of it) can tip the scales. I think clothing is the hardest for many to get their heads around and can be very expensive. Toys creep in all over, with cameras and electronics heading up the list, along with a host of "handy" trail gadgets. Books are another brick in the pack. A lot of little things can add pounds quickly. Nothing is lighter than leaving it at home.
I'm of a mind that any kit can survive *one* heavy item for the user's comfort or budget, like a thicker sleeping pad, or a DLSR camera.
And always,always, HAVE FUN!