Lord Vishnu is known as the preserver and is always ready to come running to his devotees in times of distress. The following is a simple ritual that can be done by families to maintain their safety, happiness and wealth. In the evening (around sunset), sit in front of a photo of Lord Vishnu and light a lamp. Then sit with your family members and chant the following mantra :
ॐ नमो नारायणाय गोविन्दाय हरे नमो वासुदेवाय कृष्णाय हरी ॐ
om namo narayanaya govindaya hare namo vasudevaya krishnaya hari om
Place a banana in front of the lamp while chanting this mantra and shower the base of the lamp with flowers after each repetition of the mantra. After the pooja, cut the banana and share it among the family members.
Chant the mantra 108 times, preferably on every thursday. This ritual can be done as a prayer to get Lord Vishnu's blessings for a particular event like a marriage or exam also.In such situations, continue the ritual for 7 consecutive thursdays.
With the blessings of Lord Vishnu, your family will be safe, healthy and happy always.