Think seriously about everything you take. For example, even when I have to gut fish, I only take a 1-oz paring knife. It is a cheap $2 one from WalMart. It does not hold the edge long (good for a week gutting fish), then I throw it and use another. I use old vinegar bottles for water. Old pop bottles or water bottles are even lighter but weaker. I quit using Nalgene bottles years ago!

Only take exactly what you need in personal items. The small travel size toothpaste, smallest sunscreen bottle, etc. I have titanium pots and cup. Even for a 10-day trip, I only need one pot with lid, spork and cup. I have few electronic gadgets. The only spare battery I take is for my camera. I have the smallest, lightest head lamp. Sometimes I only take the small key-chain light. I only take a repair gear on long trips. I check gear before I go and have never had anything break on an overnight trip. I only take spare shoes (crocks) if I anticipate many creek crossings daily. No towel - I wipe off with my undershirt then wash the undershirt at the end of each day. First aid is minimal. I know the FS people do not like this, but I do not take a trowel. It takes a bit longer but I have always been able to dig a "cat hole" with a stick, rock, or tent peg.

Food is very personal. Just keep track of what you bring back. I have mine now figured just right - only a few ounces left, if any at all, at the end of the trip.

I am like OM - I only carry 1 liter water, often less and use chlorine dioxide tablets. I used a Sawyer Squeeze on my last trip and was pleased with it. It allows you to filter only what you drink at each rest stop.

The more experienced you get the more comfortable you will feel about being more "minimalist". You have to decide if the "comfort" you get in camp is worth the weight of a "comfort" item. The actual "necessities" for backpacking are really minimal. On my spreadsheet I code my items as must have and nice to have. I only allow 1-2 pounds of "nice to have" items. If a major goal of your trip is fishing, then of course, some minimal fishing gear will be a "must have". One of my main reasons for backpacking is photography, so I take a camera. My camera is 8 oz.- not the lightest but suits my needs.

I looked up the current price of the sleeping bag I now have- and if I had to buy it now it would be $700!! Reducing weight by buying a new sleeping bag can be very costly. So I agree with others. Save that until you get some unexpected windfall or gift.