It's fast becoming the most widely-used lure/bait combination and is consistently an excellent Salmon producer.

When wrapping a bait fillet on a Kwikfish®, remember it should be centered around the belly screw-eye which is the balance point of the lure. Be sure it is tied on with the skin next to the lure. Use a fillet of herring, anchovy or sardine (sardine is the most popular and is available in most sporting goods stores).

 
Fillet each side away from the backbone and cut into rectangular pieces 3/5" x 2-1/4" for the K14 size; 1" x 2-3/4" for the K15 and 1-1/8" x 3" for the K16. Your bait fillet doesn't have to be exactly those dimensions, but you'll find these sizes to be a handy reference. It's important to have the fillet correctly positioned so that you maintain proper lure action once it's all put together.
Split the fillet halfway so it can be fitted around the belly eyelet, then begin wrapping with transparent thread. I prefer Kwikfish® Stretchy Thread which can be found in tackle shops, or small diameter monofilament (2- to 4-lb. test). Secure it with 30 to 40 wraps and finish with at least three half-hitches. Some anglers use small orthodontic rubber bands to hold the baitwrapper in place.
A fresh baitwrapper puts out the best scent trail so it's recommended that you replace it every hour or so. Many anglers will wrap up several lures the evening before and then freeze them for use the next day. This saves valuable fishing time. The fillet lays out a scent trail and the Kwikfish's® action provokes the strike. A real winning combination!