Getting the two ends of the binding together is a little bit fiddly, but it will make the whole thing look very neat and clean so it's important to see it through.

Line up the tails and fold them so they meet up nicely in the middle of the gap as pictured above. Try to leave an equal amount of tail on either side of the gap.

Unfold the binding so that the wrong sides are flat against each other and mark the line where the edges meet up on the wrong side of the fabric with a pencil.

This part of the process is shown well in another project journal, Molly's Handmade Napkins, under the Finish Binding Edge section.

Sew the two binding strips together along the pencil line.

Using scissors, trim the excess from the tails leaving a seam allowance that is approximately 1/4-inch wide. The seam allowance doesn't have to be exact (as you can tell from my wobbly cut in the picture above). 

d

Turn the newly unified strip back so the right side is facing and mark 1.25 inches from the edge. Sew it down like you did for the rest of the binding, being sure to backstitch at the beginning and ending of your seam.