It is a venerable custom to learn during each Rosh Chodesh a Posuk of T'hillim

Nshei Chabad Newsletter / It is a venerable custom to learn during each Rosh Chodesh a Posuk of T'hillim with Rashi (one can add other commentaries) from one's Perek of T'hillim (for example, if he is 20 years old, his Perek would be 21). If the Perek has less than 12 Pesukim (or 13 in a leap year), learn it more than once. If it has more than 12 (or 13) Pesukim, learn more than one Posuk, in order to finish the Perek in the course of the year (Likutei Dinei Uminhogei Rosh Chodesh, Ch. 11 Par. 4).