Although I like the shape of the bag I made for myself i need a much larger one for my sis and sil for Christmas. If I double the yarn while knitting would that make it bigger? Should I just rework the pattern? Or should I just look for something else? Thanks.
do you have a link to the pattern?
doubling the yarn (meaning holding 2 pieces of yarn together) and using a larger needle will give you a larger guage, and so a larger item. Making a guage swatch will help you understand how much size you’ll gain (and also help you to figure out the right needle size that you’ll need).
if you have a link to the pattern, we might better be able to suggest how to make a larger bag for that pattern.