If you take tennis shoes to most shoe repair places with even the most basic problem, they'll tell you that they're not fixable; you should throw them away and buy some new ones. For some shoes, that's still the best policy, but it's not the only option. Higher-quality shoes are often repairable with a little time and extra effort.
In this Instructable, I'll be sharing with you the repairs I did to bring my Patagonia Huckleberry shoes back up to snuff. The heel lining was worn through in one of the shoes, so I'll walk you through replacing the other lining.
These repairs took a couple of scraps of cloth, a little bit of thread, and couple of hours of work.
Step 1: Remove the Old Lining
The lining is attached with a single straight-line stitch in this pair of shoes. It is sewn onto the shoe inside out and flipped over the edge of the shoe for a hidden seam. Seams in contact with feet equals possible callouses and blisters.
Use a seam ripper or razor blade to tear out the old seam and remove the lining fabric. It will likely be attached with some sort of spray adhesive to several layers of foam. You will need to pry up the sub-footbed of the shoe (correct term?) and pull the tail of the fabric from the bottom of the shoe.
Step 2: Make a Pattern
Next, you'll need to make a pattern for cutting the new shoe lining. Iron the lining flat on medium heat (likely it's synthetic), trace around it on a piece of paper. If your lining is a messed up as mine, trace the best side, then flip it and reflect it across the axis of symmetry to make a full pattern. Mark out your seam allowance, so you know where to sew and have a good margin of extra fabric to attach under the sub-footbed.