Go to some hiking websites like backpacker.com or REI.com and read up on footwear. There are many options and technology improvements now other than the heavy and stiff leather boots we all grew up with. Go to a store specializing in outdoor footwear, not Walmart or Sears -- the staff will (should) be more knowledgeable about hiking footwear than the average shoe clerk in a mass retailer store. 5 miles up a trail is no place to first realize you bought the wrong shoes.
Go shopping later in the day, not first thing in the morning. Most people's feet change size during the day, getting flatter and wider after a day's activities, and return to 'normal' during sleep. So get shoes that fit you after a several hours of hiking, not just when you first start out.
Wear the socks you intend to use while hiking when shopping. Some people wear two thin socks while hiking, some wear only one. It's a personal choice, with advocates on either side. The advantage of two is you can remove one pair as your foot widens. (I'm a two pair myself). You can also swap them (inside sock to the outside, and vice versa) if the innermost sock gets sweaty. I always carry a spare pair of socks anyway and change during the day. Every couple of hours or so take off your shoes and socks and check your feet for any blisters or hot spots just starting. The process of putting the shoes back on and lacing readjusts the tightness to your current foot condition.
I once encountered a web site that illustrated different lacing techniques for sustained downhill hiking, uphill, side hill, heavy packs, etc. I cannot seem to locate it now though. I'll keep searching and post it here if I find it.