This is the basic method I used to make a little bag. I used to make them on night shift as I could make it completely by hand, but you could use a sewing machine for the side seams.
I used a piece of Aida cloth about 11cm x 25cm (4 1/2” x 10”), but any piece of even weave fabric could be used.
I folded the piece of cloth in half, then used thread to mark out the middle (on the front side) so I could centralise the design. The top line of thread (about 3.5cm or 1 1/2” down from the top) was so I knew where to pull the threads out for threading the ribbon for the drawstring.
I cross stitched a little posy of flowers and some bows but you could stitch whatever you liked (a geometric design would be good). After I had stitched the design, I pulled enough threads out so there was a wide enough gap for the ribbon to be threaded through. Put the right sides together, then stitch up the sides, either by hand or machine, making sure to keep the ribbon threading gap aligned. Turn bag right sides out.
Thread the ribbon through. I used a piece of narrow ribbon about 31cm (12”) long.
Fill the pouch up with lavender, pot pourri or whatever you want.
Tie the ribbon in a bow. All finished.