I like to add shape and fullness to some of my bags without having to add any gussets (side inserts to add depth). There’s a couple of different methods that I favour.
The first is by adding inverted box pleats along the top edges of the bag before adding a top band. This is where you make two folds in the fabric, facing toward each other, any distance apart.
After folding the fabric over at the desired positions, I press the first few inches of the fold, so that once stitched in place the pleat is sharp at first, then the rest of the fabric has a soft fold which gradually disappears further down. Once pinned in place, I baste (temporary stitch) across the top of the fold within my project’s seam allowance.
On some of my bags I do the inverted box pleat with the two equal folds of fabric close together, so that they meet in the middle. This gives an altogether different look.
The next method I like to use is adding darts to projects, which will add body and depth. Here I have added darts to the bottom corners of a clutch, so that it now has some fullness rather than just being flat and, along with the curved edges, it looks really elegantly shaped. On a pattern, a dart will be indicated with a triangle. The dotted lines being where the fabric is to be lined up and stitched together.
Another method I use is the ‘sugar bag base’. You stitch down the side, along bottom and up other side of the bag front and back panels. Then you flatten the corners the other way so that the side and bottom seams align. Measure across the corner to desired base width, draw a line and stitch. Trim off excess fabric from corner, repeat with other corner and there you have it, a bag with a base!