I made this bag sometime last week. Mostly, I saw the fabric in the remnants bin and decided it was a good idea. I didn't have any patterns, so I pretty much winged the whole thing. Hopefully, I took enough pictures for you to figure out what I did. I'll try to explain it along as well.
Okay, so first cut some fabric pieces.
1 - 12" X 19" rectangle (back side and flap)
1 - 12" X 9 1/2" rectangle (front side)
1 - 31" X 3 1/2" rectangle (sides and bottom)
1 - 3 1/2" thick from selvage to selvage (strap), or a ready to use strap.
small strip for closure (optional)
Next, put together the main part of the bag. I really made this easy and didn't deal with hiding the edges that are sewn together since I figured it was in the inside. I did, however, use some fray-check so the bag wouldn't fall apart on me. :-)
1. Fold down (right side out) and sew the short edge of the sides/bottom piece. This will make it a clean appearance when it's attached. ( I did this after I pinned down everything... believe me, it's much easier doing it first).
2. Attach the front to the sides/bottom piece. Start with the bottom piece. Align the center bottom edge of the sides/bottom piece to the center bottom edge of the front with the right sides facing each other. Pin down.
3. The next part is tricky. You need to make a diagonal cut on the sides/bottom piece so the edge can continue to follow the side edge of the front piece. The cut will basically be the size of the seam allowance that you'll leave. I cut it in about 3/8ths an inch. Pin the edge to the edge of the front, again with the right sides facing each other. Do the same on both left and right sides.
4. Sew the sides/bottom piece to the front piece. Just follow the edge, around 3/8ths inch seam allowance. Remove the pins.
5. Fold in the top edge of the front piece so the top edge of the sides/bottom piece is even with the top edge of the front piece. Pin down and sew. Be careful not to catch the sides/bottom piece when you're sewing the front piece down.
6. Next, attach the back/flap piece to the sides/bottom piece. Pretty much do the same thing as before (steps 2-4), but on the other long edge of the sides/bottom piece. Have the right sides facing each other.
Note: After I made this, I was playing with some of the stitches on the sewing machine and decided to add an additional layer of zig zag stitching over the seam allowances. It'll probably help in the long run.
7. I'm sure there's a much more graceful way to do this, but this bag isn't easy and fast for nothing. :-) Clean up the edges of the flap. I start this by cutting a small straight slit onto the back/flap piece where the top edge of the sides/bottom piece ends. The slit should be about the same size as the seam allowance. Now, fold in (right side out) along the side edges of the flap. Do the same for the far side of the flap. On the two corners, fold the corner down (like a dog-ear fold) then the sides. You may need to cut a small part of the corner so that it's well hidden under the folds. Should look like the picture.
If you haven't noticed by now, I've been pinning then sewing. An iron would also help immensely, but, I was lazy... at least til I actually had to bring it out.
Anyway, once that is sewn together, you can invert the bag right side out.
8. Next, I make the strap. There are several ways you can do this. You can buy a ready to use strap. Or you can use the same fabric and make one. (if you buy one, you can skip this step). I chose to make one... mostly because I forgot to look for one when I was at the store... oh well... I saved money. :-) I cut a rectangular strip pretty much from selvage to selvage about 3 1/2" thick. I folded it in half,with the right sides together, and sewn along the edge. Then I painstakingly inverted the long strip so that it was back to rightside out. Use an iron to flatten down the strip with the sewn in seam in the center. Clean up the edges by folding into the strap. I didn't sew this down, because it got sewn down when I attached the strap to the bag.
9. Attach the strap to the bag. First use pins to align the strap to the center of the outside of the sides/bottom piece. I pinned it down to about 1 1/2" down. Sew in an X and a box, like shown. Do the same on the other side of the bag, making sure not to twist the strap.
Okay, so you're pretty much done. Now, it's just a matter of if you want to put closures. I used D rings and some extra fabric to make small strips.
10. (Optional) Make a small strip about 9" long and a little thinner than the flat side of the D ring. Cut the strip into two (a 3" piece and a 6" piece). Attach the 3" piece to the flap side and slide two D rings in then sew on to close the loop. Folding in before sewing keeps it neat. On the 6" strip, fold down one side so it has a handle, and sew in. Attach the other side of the strip to the bottom of the front side of the bag. Folding in before sewing keeps it neat.
That's pretty much it. I went thru and put some fray check on open edges that I saw.
It's my version of an easy to sew messenger bag. Hope I didn't confuse you away.