I know you may find it odd. But Hinduism is not spiritual or material based. So what should be done if a spiritual person wants to become materialistic. (Shankaracharya also went to a King's body to experience Gaarhasthya. I know we cannot relate this incidence here, nor can we compare ourselves to ShreeAdiShankaracharya, but still)
Very simple - just think about material things.
dhyayato visayan pumsah
sangat sanjayate kamah
kamat krodho 'bhijayate
While contemplating the objects of the senses, a person develops attachment for them, and from such attachment lust develops, and from lust anger arises.
krodhad bhavati sammohah
From anger, delusion arises, and from delusion bewilderment of memory. When memory is bewildered, intelligence is lost, and when intelligence is lost, one falls down again into the material pool.
From thinking about stuff, association is born. From association, desire. From desire, anger (when desire is not fulfilled). Anger -> Illusion -> Memory bewildered (as to what is right or wrong) -> Intelligence lost -> Nasham (destruction).
All you need to do is mentally keep thinking about material things (food, money, power, women, prestige) and associating with materialistic people, and you'll automatically develop desire and attachment towards those.
Spirituality is ego-less condition of our being. In, non dual terms, indwelling is our real nature is spirituality.
After defining spirituality as above in non dual terms, I would like to attempt to answer how to become spiritual, not following which, one can be material. As darkness is nothing but absence of light. So, To become material one has to objectify the self only. One can objectify the self by going against these verses said by Adi Shankar (Atma Shatakam)-
I have no hatred or dislike, nor affiliation or liking, nor greed, nor delusion, nor pride or haughtiness, nor feelings of envy or jealousy. I have no duty (dharma), nor any money, nor any desire (kāma), nor even liberation (mokṣa). I am indeed, That eternal knowing and bliss, the auspicious (Śivam), love and pure consciousness. (Verse 3)
See, you can easily become material (though you/we already are) by converting real I into psycho-phyical I or removing not/nor in the verses.
Same procedure you can apply in other verses as well.
I have neither merit (virtue), nor demerit (vice). I do not commit sins or good deeds, nor have happiness or sorrow, pain or pleasure. I do not need mantras, holy places, scriptures (Vedas), rituals or sacrifices (yajñas). I am none of the triad of the observer or one who experiences, the process of observing or experiencing, or any object being observed or experienced. I am indeed, That eternal knowing and bliss, the auspicious (Śivam), love and pure consciousness. ( verse 4)
I do not have fear of death, as I do not have death. I have no separation from my true self, no doubt about my existence, nor have I discrimination on the basis of birth. I have no father or mother, nor did I have a birth. I am not the relative, nor the friend, nor the guru, nor the disciple. I am indeed, That eternal knowing and bliss, the auspicious (Śivam), love and pure consciousness. (Verse 5)
I am all pervasive. I am without any attributes, and without any form. I have neither attachment to the world, nor to liberation (mukti). I have no wishes for anything because I am everything, everywhere, every time, always in equilibrium. I am indeed, That eternal knowing and bliss, the auspicious (Śivam), love and pure consciousness. (Verse 6)
So, in actual we are already material as we identify ourselves as something which we're not. Our basic 'I' is ontologically psycho-phyical already rather than real 'I' therefore we don't need to put extra efforts to become material anymore.