You'll want camp shoes - bring flip-flops or other lightweight shoes so you can get out of your boots when around camp. These shoes have less impact on the ground and allow your feet to breathe.
Bring a headlight instead of a flashlight; you'll free your hands for finding things in your tent at night and be able to read more comfortably.
Bring various sizes of Ziploc/ditty bags to organize your gear, in your tent, in your pack, for lunch munchies, garbage, etc.…
Bring a plastic container with a lid (like a 2-cup Rubbermaid®) for a meal dish and to pack your lunches in. Bring a lightweight cup for hot drinks - the thermal cups are nice but heavy.
Instead of treating blisters, try to prevent them. Make sure your boots are well broken in by wearing them as much as you can before the trip. Tape any places on your feet that you know are prone to blisters before you start hiking. Athletic tape usually stays on better than moleskin. Tape will stick better if you first apply a coat of Tincture of Benzoin on your skin.
Bring a bandanna or two; they can be used as a washcloth or towel, worn under a hat or alone to protect you from the sun, a strainer for water to strain the gunk out, a headband to keep sweat out of your eyes, a wet scarf to wear around your neck to cool you on hot days, a first aid item to staunch blood flow or to use as a sling, and even as it was originally intended, as a handkerchief! In fact, if you tie a bandana on a loop of your backpack shoulder strap, you can have it handy for your nose, which sometimes seems to run often while you hike.
Bring a small notebook and pencil and make an entry every day, add a sketch or pressed flower. These are great to remind you of the trip later and give you a place to write down book, movie and other ideas you glean from fellow trip participants. Limericks written on the spot are always appreciated!
On backpack trips, remember every ounce will be carried on your back. Bring small sample sized toiletries, double duty clothing to layer and efficient backpacking gear. Don't bring blue jeans - they weigh too much, and cotton takes forever to dry. Splurge and buy a Thermarest - everyone I know who has one can't remember how they slept on foam pads.
Hydration systems like Camelbak and Playtypus are lightweight and make it easy to stay hydrated when backpacking. Bring at least one water bottle to mix flavored drink mixes in.
A collapsible bucket can be a real convenience - you can use it to filter water from, to clean up, rinse clothing, and for soaking your feet at the end of the day.
Pay attention to the suggested first aid list on the gear list you received -- If you are not allergic to NSAIDs (non-steroidal anti-inflamatory drugs), carry ibuprofen with you. It comes under the retail name of Advil, but generic will do fine. None of the other anti-inflammatory medications will be as effective with the soreness you get from hiking. Some of those that are ineffective for the joint pain and muscle soreness include Tylenol (great for fever) and aspirin (a good pain reliever but not effective on swelling). Always take ibuprofen with food to prevent stomach problems.
Always bring a stocking cap - it can make the difference of whether you are warm at night or miserable.
Never leave anything of value in your car at the trailhead. Always take your return air tickets and identification with you on the trip.