Before starting, you need to make a decision about whether or not to remove your basting stitches. I decided to leave them in except on the two edges of the quilt that needed further manipulation to create a seam allowance. I also removed all of the papers I had used in making the quilt.
The first step is to finish the edges of the piece so as to create a minimum 1/4" seam allowance. The edges are not all the same. Two opposite sides will match, and the other two opposite sides will match each other, as well.
I set myself up on an ironing surface, -- my wide ironing board. I added a good light source, and used my little Clover iron, as it is much easier to manipulate around the little corners.
Two of your sides might not need any further work, if you, while you were joining the hexies, you extended your stitches along the seam allowance about 1/4".
The other edges will appear somewhat ragged. The folded bits will need to be straightened out and thoroughly pressed. You may find that your hand stitching has accidentally caught some of the seam allowance. Some times just a gentle tug will loosen it without the stitching being torn out, and sometimes you may have to remove a little bit of the stitching and re-stitch the joining. In pressing the edges straight, I used just a quick spritz of Best Press, but a quick spritz of water would probably work just as well.
After the edges are all straightened, give the over all quilt a quick press as well.
Next you need to cut your batting,and backing to size. I don't have a really good table to do this on. Depending on the size of the quilt, a double bed might work just fine. First I spread my batting on the table, lining one side up with one edge of the table. Then I placed the pressed quilt top on top of the batting, allowing at least 2" of batting beyond the edge of the quilt.
Then I carefully cut off the excess batting, maintaining that 2" extra on all sides of the quilt.
I try to keep the excess batting in as large pieces as possible, as I can later machine stitch them together for another project. But this will only work with a flatter cotton type batting. The more common polyester batting has to be stitched together by hand using a large herringbone stitch. More on that later.