Make sure your wire is pre-tinned with a clean abrupt transition from the tinned portion to the insulated portion.

Carefully position the wire over the solder pad so that transition point is at the pad edge.

Place a small amount of flux on the pad and tinned wire.

Place a very small bubble of solder on your iron tip.

Just touch and release this solder bubble to the pad/flux/tinned wire junction (minimum time on the junction).

The solder joint should appear shiny and smoothly flowed over the tinned portion of the wire with no peaks or bumps sticking up.

Carefully trim off the excess tinned wire that is hanging off the solder pad with a sharp scalpel or Fiskars micro scissors.

Any residual flux can be easily "blotted" away by sliding a cut piece of paper between the LED's solder pads. Click here for a visual explanation. 

Test every wired LED before you assemble it into your project.

If you need to color tint your wired LED, do so after it's wired and before you assemble it into your project