Shavua Tov

The holy Ari, the greatest kabbalist of Zefat, explains that Rosh Chodesh, “first of the month,” can be more literally translated as the “head” of the month. Just as the head controls the body, so the head of the month controls the month. In other words, if we work to reach our highest possible potential as humans and as Jews on Rosh Chodesh, we will guarantee ourselves a more powerful and positive month.
The holy Zohar [the first textbook of Kabbala] goes further and tells us that we can even improve our ability to transform Rosh Chodesh by maximizing our energies in the Shabbat before it, this Shabbat,since, “miney misvorchin kuleyyomin” “from it (Shabbos) are blessed all the days of the week” (to come)]. This means that the entire coming month’s level of success depends on what we do during the 25+ hours of Shabbat (i.e. from sundown on Friday till you can see three medium stars on Saturday night). Making Shabbat as kodesh (‘kodesh,’ usually translated as ‘holy’, in fact means ‘separate’) as possible, meaning separating Shabbos by our thought, speech and action from the weekdays, is what draws down the most blessings.
Some Jews have the custom to say the entire book of Tehilim (Psalms) on the morning of Shabbos Mevorchim. 
 source