First choose a piece of material and cut it to 30cm x 12.5cm (11.3/4" x 5") I have used a cotton linen mixture for this one, then over lock all sides to prevent fraying. If you don't have an overlocker pinking shears are just as good. Fold over 1.5cm (1/4") on both short ends and press. Add a piece of piping to one of the short edges on the wrong side of the material and stitch close to edge on the front side. Also looks good if you use a contrast piping.
Find the centre point and mark or pin top and bottom and taking the piped edge, right sides together place 4.5cm (1.1/2") over the centre line and pin. Bring the remaining side over leaving 2cm (1/2") beyond the piped edge.
Now stitch down each side approx 1cm (1/4") in from each side.
Turn the unpiped side right side out which will give you a pocket, gently push out the corners, then fill with filling of your choice (I used lavender for this one) pushing it down so you get as much as you can in there.
Then turn the other side out and distribute the lavender ( you can always add a little more at this stage and then give it a good shake). This will give you in effect a double pocket so whatever you add to your sachet won't spill out. If you prefer the closure to be central, put the piped edge onto the centre mark.
Finish off with whatever you fancy, I added a bit of raffia but you can add anything you like, buttons, ribbon or lace also works really well.
Hope this was useful and you try some for yourself.