Front, modelled by a delightful though rather pudgy pillow:

Back, same:

Click here to see gallery pictures, on a proper human being.This is the first proper tute I've really made, so I'd love some feedback on it! I pretty much winged the pattern after I found the fabric.
Four Pattern Pieces:
MeasurementsA: Chest measurement + 5"
B: Distance from beneath bust to hips, or however long you want the top to be + 2"
C: Distance from collarbone to middle of back + 2" (about the length of your bra strap)
D: Distance from beneath bust to collarbone
E: Chest measurement divided by 4 + 4"
Cut one of piece 1, and two each of piece 2, piece 3 and piece 4 out of your fabric.
You will also need a fairly substantial amount of ribbon, and a piece of elastic 3" shorter than your chest measurement.
Directions1. Fold both piece 2s in half lengthwise and sew along the edge, then turn right sides out. Hem raw ends.

2. Sew each piece 3 to a piece 4 on two edges, right sides together, with a piece two trapped in between. Turn the right way out, turn in the raw edges and hem.

3. Hem the bottom of piece 1, and turn over the top to make a hollow channel, about 1" wide.

4. Topstitch the two triangular pieces to the back of piece 1 with an overlap of about 4", just below the hollow channel.

5. Fold the garment in half, right sides together, and sew the edges up until just below the channel.

6. Thread the elastic through the channel, then sew the ends together so it forms a loop. Turn under the raw edges of the channel and hand-sew them together.
7. Sew the shoulder straps to the back of the shirt. The easiest way to do this is to try the top on inside out and pin them in the most comfortable place, then topstitch them there.
8. Cut 8 1" pieces of ribbon and cover the ends in clear nail varnish to prevent fraying. Fold each in half and sew to the back straps at regular intervals.

9. Thread ribbon through loops in a criss-cross pattern and tie in a bow (see photo).
10. Cut a short piece of ribbon, fold into thirds and gather the centre to make a bow. Where the two triangular pieces meet, sew the bow.

If you are larger of bust, you may wish to add darts. Or you could just use a proper busty pattern piece for that section.
You can use this tutorial for anything you like, modify it any way you see fit and sell things made from it. Just don't pretend you wrote it!