I had two pairs of jeans that I didn't need. One pair had a rip in the butt-area, and even if I fixed that, it would look awkward.
My other pair was a bit baggy because they were hand-me-downs.
So I made the best of it and combined them, and this is what turned out.
:D

Throughout the project, SAVE ALL OF YOUR SCRAPS!

Step 1: Gather Your Materials

To make these jeans, you will need:

Two pairs of jeans you are willing to cut up
Thread and a matching bobbin (I used denim thread)
Sturdy sewing needle for machine and hand sewing (When you go to the store, the needle's packaging says denim)
Pins!
sewing machine, scissors, etc.

The jeans I used for the bows had a rip in the butt. They are the lighter pair.

Step 2: Start Cutting!

Take your pair that will become the bows.

Cut open the jeans on the inside seam along the red line in the first picture.

Cut off the thick seams on the inside of the leg and the bottom of the jeans. (see the red line in the third picture).

Step 3: More Cutting

Fold up the jean leg 3-4 inches up, and cut a strip. (see red line in picture 1)

Continue cutting until you reach the main butt part of the jeans.

Now, cut along the seam in the middle (see red line in picture 3).

Fold up and cut another strip, this strip may be longer and thinner.

Repeat cutting strips with the other leg.
You will have about 4 strips per leg.

Step 4: Start Sewing

Take one strip and fold it in half lengthwise, right sides in. See pictures 1 and 2.

Sew along the yellow line in picture 2.

Repeat this with all of the strips.
Turn the strips right side out.

You may have two long and skinny strips. You can cut these in half. (see the bottom two strips in picture 4).

Step 5: More Cutting!

Take your other pair of jeans.

Turn the jeans inside out. Cut in about two inches towards the crotch, then down to the ankle. Cut a bit more off near the ankle. (Picture 2)

Fold the jeans in half. Cut the other leg, tracing the first cut. (See picture 3).

Unfold. Now you have cuts in both jean legs.

Step 6: Hem It

Take your jeans. Roll up the raw edges so they are tucked in to hem. See pictures 1, 2, and 3.

Sew along the yellow lines in picture 4 to hem it.

Step 7: Pinning Time

Put your jeans on inside out (it's a bit awkward).

Pin the strips on to one leg, evenly spaced. (see pictures 1-6).

Trim the extra fabric hanging off. (Picture 7)

Mark where you will sew the strips on to the jeans. Number them so you can replace them, and mark their location on the jeans.
(picture 8)

Take the strips off and use either the zigzag stitch or a serge stitch to prevent the edges from fraying. (pictures 9 and 10)

Step 8: Attatch the Strips

Repin the strips according to your markings. (picture 1)

Sew the strips to the first layer of the hem. I hand sewed mine because my machine would not fit. (picture 2)
Be careful! The denim will be thick. Use a thimble or something similar.

If you turn in right side out it will look like picture 3.

Step 9: Second Leg

Take the rest of your strips.

Align them with the strips from the other leg, and trim them to the same size. (picture 1)

Number the new strips and use either the zigzag stitch or serge stitch to prevent the edges from fraying. (picture 2)

Fold the jeans in half, and pin one side of the strips on to the jeans. Align the strips on one leg to the strips on the other leg.
(pictures 3-5)

Put the jeans on inside out and pin the other side. (pictures 6-8)

Take the jeans off and sew the strips on as you did with the other leg. (Pictures 9-12)

Step 10: Creating the Bow

Take the scraps of fabric you saved. You can cut rectangles from the top of the jeans (see pictures 1-3).

You will have the scraps that you trimmed from the strips.

Cut the strip open so it is long. Then, fold it in half lengthwise, right sides in. Sew along the long side. (see pictures 4-6).

Turn the strip right side out. (Picture 7)

Wrap the strip around the soon to be bow on the jeans. (picture 8).
Sew tightly, but not attached to the bow. (yellow line on picture 8)

Trim the excess fabric. (picture 9).
Use the zigzag stitch or serge stitch along the new raw edge that you just cut. (picture 10).

Flip the strip right side out, and turn it so the seam is on the inside. (picture 11).

Repeat with the rest of the bows (pictures 12-14).