Im very good at fileting fish, however how do I keep the skin from curling up on the sidess when I crisp the skin.

Okay. Then the holding trick is what you need. Make sure your finger tips are on the perimeter of the filet. Trust me, this is the way to straight crispy. Apologies for not being more direct. Here's a link to my man Gordon on the method: http://www.youtube.com/watch?v=wSrR0CsbGWs

i know how to get the skin crispy. that is not the issue. the issue is keeping ALL the skin straight while crisping it. most notably the skin right around the sides of the filet. Im using the technique mentioned above with my branzino filets but the sides curl up. so I need some better advice...

Okay. First, if its a scaley fish, easy. After descaling the filet, make a few very light, shallow slashes on the diagonal of the fish. Then get your pan very hot, preferably cast iron, add oil, place filet scale-side down, and gently hold the fish down using your finger tips, applying light pressure, don't worry about your hand it will be fine, no matter how much it spits, hold the filet like this for about thirty second and release. Optionally, after you flip the fish to a side of the pan, add a chunk of butter and tilt the pan to one side so that the filet is opposite of the pooling butter, baste the skin constantly for another minute or so. Optionally, get some Wondra flour and season it with whatever you like, along with some salt, place the filets in skin-side down and lift out, shaking off excess flour, do not coat the flesh side, this will guarantee crispy skin, just remember to slash the skin and hold it down in the pan.