It is believed that Diwali is the best time to appease Goddess Lakshmi. Rituals performed during this time yields best results and Goddess showers her devotees with wealth and prosperity.
Here is a mantra that can help you fulfil all your wishes.
'Om namo bhagwati padhya padmavi om hrim om om purvey dakshinay uttaray aash purya sarvajan vashya kuru swaha.'
Place a portrait of Goddess Lakshmi and conduct Lakshmi puja. Then chant the above mantra 108 times. Use kamalgatta rosary for chanting the mantra.
After chanting, blow 10time in the four directions.