I can vouch for this statement. Honestly, the hardest part of making a simple LED set up, is working out the correct resistor(s) needed for the power supply you'll be using. But all you have to do is hop over to the LED Calculator website, and it'll do all the work for you.
It's darn near impossible to muck up soldering an LED to a wire. Just let your iron heat the wire and/or lead just enough to melt the solder when it touches them. Capillary action takes care of the rest. Then seal everything up with some shrink tube or electrical tape. It doesn't need to look pretty. It'll all be hidden inside the shoe.
Exactly, What I used was hot glue to keep all the wires safe from touching, it's easy moldable when cooling and turns into a rubber type substance.
Brad