This is the skirt I started with.
It had an underside, that I cut off to use for the bib of the apron.
Like so! I folded it until it made the right size for the bib.
I cut the skirt exactly in half, stopping at the elastic waistband.
I cut the other half of the skirt off right under the waistband and then cut the waist band in half.
I then held the bib section up and measured from the top of my tank top to just where the apron waistline reached (higher than a normal skirt).
Then I pinned it in place and sewed it straight across.
I used the drawstring from the skirt to make the halter, which turned into regular straps because the bib stuck out too much and didn't actually cover my shirt. :P
I also put a button on one end of the cut waistband and a loop on the other.
Then I made a little flower and sewed it to the top. :)
I think it turned out pretty cute. :)