Prolong lucid dreams by spinning your body or falling backwards in the dream (suspected of prolonging REM), and rubbing your hands (prevents you from feeling the sensation of lying in bed).
Take care while spinning. Remind yourself even as you spin or fall that you are dreaming, as you will find yourself in a completely different location when you stop spinning or hit the ground and may lose lucidity otherwise. If you feel a dream 'shakes' or is about to fade out, look down to the ground and visualize your surroundings, reminding yourself you are dreaming.