This project has been inspired by Crafta La Vista's Halloween Spider Fascinator; it is mainly a more sophisticated version that you can wear at any fancy party (Halloween or not)!
This project took me a long time because I made the choice to sew instead of using glue, for a nicer finish. If you just want to make a costume piece, thought, you may want to use plain old super glue!
Start by drawing a egg shape on your interfacing (on the non-sticky side, of course) and drawing a line from around the center of the shape right to the larger edge. Don't worry if it's not a perfect shape! This base is loosely based on Kerli's fascinator tutorial (http://iamamoonchild.net/?p=1512).
Cut your egg shape and iron it on the wrong side of your solid fabric (you can glue it if you only have sew-on interfacing).
Cut your fabric, leaving about a cm around the edge of the interfacing shape. Cut along your straight line.
Fold your the two edges and glue them in place, making a sort of flat cone (I like my headpieces really flat, but you can always make it "pop" more).
Fold the edge of the fabric over the interfacing base and either glue or sew it. You can cut notches in the fabric where the edge is rounder, it will make the gluing easier. Sew your sequin trim around the edge.
Cut semi-circular shapes in your lace fabric. I chose to make two small ones since it's a thick fabric.
This part gets a little tricky. Frill up your lace by making large stiches on the round side of our shapes and gathering it. It seems really hazardous, but once you'll get to the sewing, you'll have more control on your lace bits.
Sew the gathered lace on the fascinator base. Don't worry about getting a neat and tight finish, but make sure your lace fabric has the desired amount of fluff and shape.
Sew or glue your spider on your lace (to hide the stitching and make a pretty finish). Finish the fascinator by gluing or sewing a hair comb or a hair clip inside! Voilà!
Of course, you can always make it more or less elaborate, or make it a pink goldfish fascinator. The sky is the limit!