When you are hiking you have to remember one thing, your feet are your number one priority! Without the right gear on your feet, you're practically inviting blisters and a nasty hiking experience!

The crucial thing to remember about preventing blisters is that it requires a good pair of hiking boots and hiking socks.

The first thing you need to do is to BREAK IN YOUR BOOTS!
Even those boots that come practically broken in for you still need to be stretched out and broken in before heading out on a hiking trip. This is especially true for heavier, leather backpacking boots. So, take the time to walk around in your new hiking boots around home before heading out for a long hike.

You need to make sure you have a GOOD FITTING BOOT!
If your hiking boot fits almost fine but causes some hot spots (where the skin gets hot due to the boot rubbing on it) on uphill climbs, a cure for this is to use hiking boot inserts. These inserts are inserted into the bottom of the boot, taking up some of the dead space. I did this with my favorite hiking boots and it worked like a charm. On uphill climbs, particularly steep ones, I felt hot spots on the back of my ankles, leading to small blisters over the course of long walks. Inserting the inserts completely got rid of this.

Always hike wearing HIKING SOCKS!
Never use cotton socks. Cotton socks quickly get wet, bunch up and begin to rub against your skin - causing blisters. Hiking socks are designed to not only provide additional padding for your feet, but to not bunch up and be more of a hindrance than help. A good pair of hiking socks are not cheap (somewhere around $15/pair), but you don't need many of them either.

Also wear LINER SOCKS!
Liner socks should also always be worn when hiking. Liner socks, which are made of polypropylene, remove perspiration off your foot and transfer it to your hiking sock. Liner socks are a crucial piece of equipment for preventing blisters on longer hikes, as by keeping your foot dry half the battle is won in the war against blisters.

Are your boots LACED PROPERLY?
Make sure your hiking boot is properly laced. A hiking boot that is not laced tight enough can cause your foot to move around quite a bit. On the other hand, don't lace your boots too tight, as this will cause your feet to swell causing you pain. Try playing around with various degrees of lace tightening/loosening to find the right spot that keeps the boot from moving around but yet keeps your feet comfortable. And be prepared to adjust the tightness while out on the trail, too, as once you begin hiking you may need to tighten/loosen the boots a bit to get just the right fit.

And finally, Don't forget the MOLESKINS!
Use moleskins to cover up "hot spots" that can turn into blisters. Moleskins are like a bandage that goes over the blister, preventing the boot/sock from rubbing against it. Even if your hiking boots fit perfectly, always carry moleskins with you.

Now that you know how to properly prevent blisters while hiking, happy trails!