Blisters are often caused by wearing too small of shoe.  Feet swell as the mileage grows. 

When fitting and purchasing your hiking shoes/boots follow the step below:                            

1.  Wear two pair of socks when trying on hiking boots.  First a liner sock that fits snugly to your foot.  Next, put over the liner sock a blended wool sock for cushion.

2.  Ignore boot size and continue to try on boots until they are uncomfortably large fitting.  When you believe the boot is just too large, then reduce the size by ½ size and continue to set 3.

3.  Once you think you have the correct size remove the boot insole and stand on the insole.  Your foot should have a 1/4 clearance on both sides and rear (at the heel).  The toe should have a minimum of a 1/2 clearance, but I prefer 1" clearance. 

4.  Put both boots on and walk around the store.  Wiggle your toes to make sure they are not touching or rubbing on the inside of the boot.

5.  Purchase extra socks that you are wearing and carry the extra set with you on all hikes.  Change your sock when your socks become damp.  Take your boot off at the lunch break so that your socks can dry.

6.  If possible the hiking boot should be breathable and water-proof.

Good luck!