Wash new towels before using them to make them more absorbent. Many towel manufacturers coat their new towels in a fabric-softening finish that keeps them looking fluffy when they are on the display shelf but decreases their absorbency.
Adding vinegar to a load of towels in the washing machine can boost absorbency and also help retain the towels' vibrant color. The Turkish Towel Company suggests adding 1 cup of vinegar during the rinse cycle to eliminate traces of detergent that otherwise diminish the absorbency of the towels.
Do not use a fabric softener when washing towels; it can reduce towels' absorbency.