No such thing as ‘lucky day’ or ‘lucky color’ etc. in Buddhism.
Using well-spoken words, humility, contentment, gratitude and hearing the good Dhamma; this is the best good luck
The Buddha considered such practices as fortune telling, wearing magic charms for protection, fixing lucky sites for building, prophesizing and fixing lucky days to be useless superstitions and he expressly forbids his disciples to practice such things. He calls all these things ‘low arts.’
“Whereas some religious men, while living of food provided by the faithful make their living by such low arts, such wrong means of livelihood as palmistry, divining by signs, interpreting dreams… bringing good or bad luck… invoking the goodness of luck… picking the lucky site for a building, the monk Gotama refrains from such low arts, such wrong means of livelihood” by Venerable S. Dhammika