A good tip I use is that you should be able to wear all your clothing at once as part of a coordinated layering system. That will minimize "extras." Clothing requires a lot of volume, sometimes even an entire pack, and is often surprisingly heavy. (Use a good scale to weigh everything.)

Wash and dry clothing as you travel. Stop at a suitable water source on a sunny afternoon, wash your clothing, give yourself a sponge bath, and put your clothes back on damp. It's refreshing, and by the time you stop for the day your clothes are clean(ish) and dry. If the weather's harsh or there's not enough water, it won't kill you to skip a day--embrace the stink. On extended trips an occasional stop at a laundromat or the house of a generous host is extra welcome.

Look at single-wall tents like at Tarptent for shelter. There's a learning curve dealing with condensation, but weight, volume and cost savings are appreciable.

Consider a quilt instead of a sleeping bag.