In reply to Luke Brisco:
Got lots of experience in this! Tried to make my own backpacks, pouches, running vests, waxed jacket etc but my sewing machine decided to crap it's pants. Might be just me but I have found that making kit has become an addiction. Most of them turned out pretty well but I could of done much better. For learning resources I mostly used Youtube and channels like learnMYOG and Zipworks, you can pay a few dollars to get some templates. They teach you how to sew it from start to beginning.
Making kit is no serious joke, it is surprisingly hard and holds a lot of frustrations, but it is also really satisfying and fun. I got overenthusiastic when I started and jumped straight into the deep end, wasting fabric and time. I would recommend making something pretty simple like a stuff sack first. Even if you don't need it, it will give you an idea of the time required and for you to hone in your skills.
From my experience, start simple and basically do trial and error. Make your own patterns and always make a prototype out of the cheapest fabric you can find.
Pointnorth does great performance fabrics at a decent price plus they ship very fast.