Go light - only carry what you need. Get a pack with a hip belt to distribute the weight off of your shoulders.
Get comfortable hiking shoes/boots and break them in prior to your trip. Carry moleskin anyway.
Wear a layer of body armor or similar moisture-wicking fabric. Have a looser outer layer handy in case it gets cold, and finally a waterproof shell in case of rain. Avoid cotton like the water-sponging deadweight that it is. Spandex biker shorts are a good alternative to underwear.
Get some good waterproof pouches for things like maps, matches, id, money and electronics such as cameras or a phone. Anything else that can get a little wet, such as toiletries, can go in ziploc bags, but ziplocs are not dependable for "absolutely cannot get wet" items.
Eat your final meal for the day about a half-hour to an hour before you stop hiking for the day to keep the aroma of food out of your camp. Keep all food, soap, and toiletries in a separate bag that can be hung from a tree limb. Especially if you have Yogis.
Keep a change of clothes in your car to change into when you return, for you shall be fun
kay.
Important items: TP, matches, first aid kit, toothpaste/brush, map, compass, emergency funds, id and medical ins. card.
Nice to have: camera, GPS - I hiked the Ozark Trail last May, and at a poorly marked intersection I ended up on a logging road instead of the trail. By comparing the trail of dashes on my GPS to my topo map, I was able to correct the error without having to backtrack for miles.
Here are two pieces of equipment I got great use out of:
http://www.msrcorp.com/stoves/pocket_rocket.asp
http://products.katadyn.com/brands-...ralight_Series_25/Katadyn_Bottle_075L_31.html
This is by no means a complete list, but these are some of the things that quickly come to mind when looking back at my last trip. Hope this helps.