Thru-Hiker: Gear and Resources for Long Distance Hikers
Fabrics And Materials Fabrics And Materials The Workshop: Make Your Own Gear Projects Articles for Lightweight and Long Distance Hikers

French Seams

Knee Articulation

Hood Pattern

Installing Wrist Elastic

Down Underquilt

Mitten Pattern

Using Continuous Zipper

Titanium Solid Fuel Tablet Stove

Lightweight Backpack

Manual Buttonhole

Basic Seams for Homemade Gear Projects

How to load thread into the bobbin

How to Check and Adjust Thread Tension

Mesh Stuff Sack

Folding Wood Burning Pack Stove

0.5 oz V8 Stove

Cat Stove

Down Quilt

Make Your Own Silnylon Stuffsacks

Henry's Tarptent & Tarptent-for-2

Basic seams for making your own gear

Simple seam:  The seam allowance is the distance between the stitching and the edge of the fabric.  This seam doesn't protect the raw edges from raveling, nor is it as strong as the felled and french seams.  It is easy to make, though, and works well for many applications.
Felled seam step 1:  The lower fabric's seam allowance is twice that of the top fabric.  Lay down a line of stitching just like in the simple seam.
Felled seam step 2:  Open up the fabric.  The longer seam allowance edge is going to be folded around the shorter one in the next step.
Felled seam step 3:  You can see how the longer seam allowance folds around the shorter one (in green).  Lay down the second line of stitching close to the edge as shown in the diagram.  It should secure all three layers of the seam allowance to the bottom layer of fabric.  You may need to secure the folded layers to the bottom layer of fabric with pins, but keep them in the seam allowance.  You'll seam seal this area anyway so pin holes won't compromise waterproofness. 
Felled seam step 4:  This is what the felled seam looks like from the top.  You will see two lines of stitching.
Felled seam step 5:  This is what the felled seam looks like from the bottom.  You will see one line of stitching.