Tulasi:

Among all articles which are offered to the Lord, Tulasi is most highly praised. Therefore one may perform perfect worship of the Lord by simply offering pure water and Tulasi leaves (Raghunatha das Goswami, Advaita Acarya). According to the Garuda Purana, Tulasi must always be offered on the naivedyam.

tulasi vina ya kriyate na puja

snanam na tat yat tulasivinakrtam

bhuktam na tat yat tulasi vinakrtam

pitam na tat yat tulasi vinakrtam

Puja, bathing and offering of food and drink performed without Tulasi cannot be considered as puja, bathing and offering to the Lord. The Lord does not accept anything or drink anything that is without tulasi.

Brihad Naradiya Purana

During the puja, one should offer Tulasi leaves to the Lord's feet. tulasi garlands may also be offered around his neck.

Some say that gandha, flowers and Tulasi should be offered at least three times, washing the hands each time before offering. The article is offered in the right hand, while the left-hand touches the right arm. Some say that offering eight Tulasi leaves is best.