I love pillowcase dresses or any dress that uses a minimal amount of fabric. I saw a dress like this somewhere and I decided it didn't look too difficult. Here is my version. It's basically a pillowcase dress but the top is a little different. I'll try to walk you through how to make one of these.
1. You'll need several things to make this top/dress - one pillow case or about 1/2 yard of fabric (My daughter wears a 3T so these measurements are all to fit that size but you can easily change them to fit your child), thread, one pkg of double fold bias tape, enough elastic to comfortably fit around your child's collar.
2. Take a stretchy shirt (not a button up one) that fits your child and trace the neck opening onto a piece of paper. Then measure about 1 1/2 inches out from that first circle and then measure about 2 inches out from that circle to make an even bigger circle. Draw the two more bigger complete circles. You will have made the pattern for the collar band for the dress. You have to draw out the larger circles because you will have to allow for room to get the dress over your child's head.
3. Cut out around the outer perimeter of the largest circle and then cut out the inside from the medium circle. Throw away everything else. Cut your circle in half. You'll have something like this half-circle shape. Put that shape on the fold of your fabric (like in the picture below) and cut out two of them.
4. You should now have two circles that look like this.
5. Place one on top of the other and cut an opening like this. Just cut the circle.
6. Now for the body of your top/dress. Fold your pillowcase in half with the opening at one end and the closed end at the other. (If you are not using a pillowcase I would recommend cutting out a 15" by 15" square for a top and a longer piece for a dress. You have to adjust the measurements for your child. I used the 15x15 method and it turned out to be a shirt for my daughter. I would probably add about 10 inches to make it a dress.)
7. With your fabric folded as in #6, cut out a 5" long piece that is about 1 1/2" deep with a curve to make the arm openings. This is opposite the fold. In the picture below, the fold is on the right.
8. Now let's start sewing. Put your two circles rights sides together and sew around both sides. Then turn right side out and press.
9. Sew the sides of your top/dress closed. Do not sew the arm holes or the top or bottom yet.
10. Attach bias tape to the arm holes.
11. Sew a basting stitch along the top of both front and back pieces and gather them slightly.
then stick your other unfinished end into that end. Sew a stitch across there to secure it but do not sew all the way across. You need to leave room to insert the elastic later.
13. Pin your gathered front and back to the front and back of your collar piece. You will want to pin the wrong side of the collar to the right side of the gathered piece and then sew them about 3/8" from the top and then about 3/8" from the bottom of the collar piece. This will secure the gathered piece and will also make a track for your elastic.
14. Insert the elastic using a safety pin and then sew the collar opening all the way shut.
14. Hem the bottom of your top/dress or sew on the bias tape.
15. Then admire your creation. Put it on your daughter and let her run in a field of wild flowers.I know I would have if it wasn't raining and 42 degrees out today.