I made a zipped pocket for the outside. Love the green zip.
On the inside I did a zipped pocket and slip pockets for 2 pens, phone and my notions tin. I used a magnetic snap as the main fastening.
I used a fairly thick lining fabric and laminated cotton bought in the Laura Ashley sale. As both fabrics are fairly thick I didn't use an interfacing.
This is the pattern I used but I made the bag slightly wider, straps longer and added pockets. Wish I'd made it deeper too.