Step 1 - Buy supplies. You will need: straight gold aberdeen hooks (#1/0, #1, #2, #4,), willow leaves (#0, #1, #2, #3), core rosin solder, flux paste. Supplies and a starter kit are available from Woo's Lures.
Step 2 - Tools needed. 18 watt soldering iron (I use 18 watt Weller # WPS18MP), cutter for solder, vice or some device to hold willow leaves horizontal. Carving or burning out a block of wood to hold the willow leaves in place for soldering is a good device you might consider. Or, you might make some sort of a mold to hold the willow leaves in position.
Step 3 - Soldering. Place willow leaf in holding device or vise with concave side up. Place a small amount of solder on end away from the hole in the willow leaf. Put a little flux on the eye of the hook and place hook end into the melted solder. You will have to use the soldering iron to keep solder liquid as you place the hook on the willow leaf. Let it harden for a couple of seconds and you're done. Wipe off any flux with a rag or it might affect your paint job. The long shank of the hook extending from the willow leaf contributes to the enticing wobbling motion of the spoon. You can vary this length by soldering the eye of the hook farther up on the willow leaf, or you can shorten the hook by cutting off part of the shank. You can also use different hook sizes. I recommend #1/0 hook for a #3 willow, #1 hook for a #2 willow, #2 hook for a #1 willow, and #4 hook for a #0 willow.