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Nail polish dries due evaporation of the solvents it contains. Applying the second coat effectively softens these same solvents. This allows the polish to return to a liquid state and be wiped away. The best type of polish for this method is thin and slow to dry. A clear top coat would work, as they tend to dry slowly. Avoid quick dry nail polishes or sprays or drops that cause nails to dry faster. Some blogs suggest that darker colors than the polish you're removing often have the best effects. That said, the rate at which a polish dries is the most important factor. It should be slow.
Select another nail polish that will not dry too quickly.