It's not rocket surgery, use a 1K resistor and make sure you put the anode to positive supply and cathode to return. The current flows through the LED in the direction the arrow points on the schematic. If the LED is really dim or off, try a /slightly/ smaller resistor, go down to 499 ohms or something. If the LED is really bright or lets the smoke out, go up to 1.5K~2K.
"Silent enim leges inter arma." -- Cicero