Try on your denim with the shoes you will wear with them most so you can get a good length.
Buy coordinating thread, typically denim gold is used but I have used red before and it looks like it was made that way.
Use the proper tools, I prefer the Jean-A-Ma-Jig by Dritz.
When I first saw this tool at my local sewing store, I wondered why I had never seen this before. When I first used it, I wondered how I ever lived with out it.
When you get close to the seam, stop, needle down, and lift your presser foot.
Slide the Jean-A-Ma-Jig under and then lower your presser foot.
Continue sewing and repeat at other seam.
No uneven stitches, no jamming up your needle on the seam, no wavy hem stitch line!
Just beautiful custom jeans.