miss the apron in any pieces. adjust gather if needed and then pin across.
at this point, i usually also check to make sure that my top band is fairly even on both sides. in the next step you are going to be sewing along the bottom of the top band. . . and while you will be sure you are sewing through one side of the top band, you will be blind to what is going on on the other side. feel along the top band to make sure it is relatively even on both sides of the apron.
sometimes i take a pin and push it straight through the gathered 