Improving your soldering technique/equipment is a great option.
You can make leads as long as you want if you know how to solder. Heat shrink it if you're feeling adventurous (or liquid electrical tape or tape tape, whatever works for you)
You obviously should not be killing LEDs while simply soldering wires to leads. Get a helping hands device, set it up how it ought to be. Make sure your soldering iron is hot enough. A lot of newbies use insufficient irons with tougher to melt lead-free solder and end up holding the iron on components far too long and killing them.