Hiking Boots
I can't stress this enough, you have to take good care of your feet. They are what carries everything else. If you are going to spend money on anything, start here. If you are just going on a short, easy trip a broken in pair of tennis shoes will do ok. If you are doing some serious hiking you need to get a good pair of boots. They need to be broken in before the trip.
For boots go to an outfitter (not Dick's, stay away from Dick's. I recommend Rusted Moon). TRY THEM ON IN A STORE, don't just buy them online. Talk with the people in the shop, they are going to be hikers themselves and can help you.
Socks are another important part of your feet. You want socks that will wick the moisture away from your skin. NO COTTON! I use Smartwool, they are not cheap but they do well.
I tend to have problems with rolling my ankle, so I wear ankle braces.
A lot of people have problems with blisters, it's very common. Women seem to be affected more than men (they are sexist and discriminate against women it seems). It is likely that your feet have never been treated like this and you will discover some new foot problems. The more broken in your boots are the less they will give you problems. Good socks will help. But in the end you're going to learn this by experience. If you feel a hot spot while walking stop right away and treat it. Deal with it before it becomes a blister. It may take moleskin, you may just slap some duct tape on it and that'll fix it (duct tape fixes everything, it really does). Prior to your trip try some hiking with a pack and see how your feet are affected.
Your feet are the most important thing you have on your trip, you MUST take care of them.
