1) Soldering iron and the grey matter associated with wielding it
2) Glue gun, or clear 5 minute epoxy depending on taste.
3) Rainbow LEDs! Or any LEDS for that matter. I Used THESE
5) Wires, solder, resistors, heatshrink.
So. First I spent some time working out what was going where and how to do it etc etc. I wanted mixed LEDs of various colours mounted all round the guitar at first, but I didn't want unsightly wires all over it, on top of that, different spec LEDs can be troublesome when wiring them up with limiting resistors in parallel and all that malarkey... The best solution I considered was to mount very bright LEDS in roughly the four corners, and angle them into the guitar body for impressive refraction effects.
I also made the decision to lose the neck pickup for battery space, this simplifies the wiring in the control cavity greatly.. The guitar sounds nasty anyway, so the FX I chose for Part Two is a real NOISE maker... I doubt I'll miss the neck pickup, and this way it will only cost me once to replace the bridge pickup with something that doesn't sound like a 1950's transistor radio.
This is what it looked like shortly after I started removing strings and knobs and was around the time I started to think 'hmm maybe I should try and make one of those instructabilly things..'