I was asked a while ago to do a tutorial on making a bow. Sorry it's taken me so long Selina. Bows are pretty easy and they're great for beginner sewers.
This is how I make fabric bows but there may be other, better ways out there.
You will need:
Needle and Thread
Sewing Machine (you could do this by hand but it's much easier with a sewing machine)
1. Cut two rectangles of fabric the same size. The size depends on how big you want your bow to be. My rectangles were about 20cm x 12cm. Also cut a smaller rectangle. This is for the tab in the middle of the bow. Mine measured about 9cm x 5cm. At this point you can finish the raw edges by zigzagging or overlocking them. I didn't because I am lazy.
2. Pin the two large rectangles right sides together. Leave a small section at one of the bottom corners free so you can turn the fabric right side out when you've sewn it. You can see the section I haven't pinned along the bottom left. Fold the small rectangle in half, right sides together, along the longest side.
3. Sew together the two rectangles where you have pinned, making sure to leave a small section free in the big rectangle. Use a relatively small seam allowance, about half a centimetre.
4. Trim the corners of three sides of the large rectangle, not trimming the corner which you have left open. Turn the rectangle to the right side. Use something, like the end of a crochet hook or a knitting needle to poke out the corners but be careful not to poke a hole in the material (sometimes I use my scissors which I don't think you're supposed to do but oh well). Push the edges you left open inside the rectangle so they cannot be seen from the outside. Turn the small rectangle to the right side. Don't worry about the raw edges because they'll get tucked in.
5. Iron both rectangles so they are nice and flat. Iron the small rectangle so the seam is in the middle of one side. This will be the back. Handstitch the opening in the big rectangle closed making the stitches as invisible as possible.
6. Hold the large rectangle between thumb and forefinger, like below, and wrap the small rectangle around the middle. At the back tuck the ends of the small rectangle in to make it neater and stitch closed. It doesn't matter if it's not really neat though, because this is the back.
You've finished. Now you can stick bows on everything. If you want to stick a bow on clothing it's best to add a safety pin to the back and attach it that way, because then you can remove it when you want to wash the item of clothing.
My bow isn't particularly even because I was in a hurry, but hopefully this gives some idea of how to make one.
If you have any questions or something isn't clear, just ask in the comments.