Yesterday I bought two tops for $1 each from a thrift store for Jemima including this plain yellow t shirt. For this project you'll need two circular doilies or embroidered pieces of linen.
Firstly, lay the t shirt out and cut off the sleeves. Turn the edge under and sew around the arm hole. Then take your doily and cut it in half. Place the raw edge under the arm hole of your t shirt at the shoulder and sew it on to make little capped sleeves. Be careful to make sure that the centre of your semi circle matches the neck to shoulder seam at the top of the shirt.
Take your other doily/linen piece and draw a heart shape in the centre on the wrong side of the fabric. The easiest way to do this is to draw a heart on paper and tape it to the window before laying your fabric over the top. You'll be able to see the shape through the fabric so you can trace it neatly. Cut out the heart carefully, nail scissors work well for small shapes.
Sew the circle onto the front of the t shirt then applique around the heart. I used my machine but you could do it by hand.
The other top I bought was this short little singlet top which I made into a summer dress. For this project you'll need a top, a fabric scrap for the heart shape, and some fabric for the skirt. In keeping with the love heart theme I cut a heart out of contrasting fabric and sewed it onto the front of the top using applique stitch.
For the skirt I used a scrap of leftover fabric that I had called Central Park by Kate Spain. I used the bottom part of a dress pattern but you could use either a skirt pattern, or just wrap a piece of fabric around the waist 1.5 times. Once the skirt was sewn I gathered the top.
Next turn the top inside out and lay it over the skirt so that the right sides are together. The hem of your top should meet the top waist section of your skirt. Pin it in place (adjust gathering as you need to) and sew around. This is the same technique that I used when I remade a 1980s dress in this post: remaking vintage clothing.
When everything is turned the right way around sew a top stitch around the skirt waist. Press the seam then finish the skirt by sewing the hem.