Last night I decided to give it a go making a pattern out of one of my own shoulder bags.
Starting to cut out the pattern using brown paper using existing bag
I made a pattern using brown paper, cut out 4 pieces from my fabric (bag with liner as the fabric on the wrong side wasn't a very good surface) and pinned it together to see how it would work as a bag and found I didn't like it.
I found it was a lot of trial and error to work out how to make my first bag. I cut the handles off, so I could reposition them, plus made them the same width, rather than tapered. Then found I didn't like the bottom of the bag curved, so I sewed a straight bottom into it and cut off the excess fabric.
The trickiest part was getting my head around sewing the straps, liner and bag all together so it came out the right way at the end. A quick google and I was on the right track, but needed to make a hole in the bottom of the liner so I could pull the whole bag through once I'd finished sewing it together.
I'm very happy with the finished result as below, just need to find something to keep the bag closed and sew the hole at the bottom of the liner. 4-5 hours and $8 for the fabric.
Finished product, minus something to keep the bag closed.