Put on your gloves or finger cots before beginning. Find the tightest fitting gloves available so there is no slippage between your fingers and the gloves (food-service-type gloves will not work as they are typically larger than your hand).
Layer the pastels on your artwork in the colors and levels suited to your piece.
Gently rub along the spot you wish to blend, always blending slowly. It is easier to continue the blending than to re-layer the pastels and preserve the color.
Remove your finger cots or gloves before blending a second time. Alternatively, wipe your fingers with the baby wipes between blending. This step will prevent the colors of your previous blend from being laid on top of the new blend.
Wash your hands with soap frequently to clean the dust and pigments from your fingers.