ghee lamps

Lighted 900*/1008 ghee lamps @ Mahalakshmi's lotus feet....remaining 108 lamps @ ashtalakshmi temple on tomorrow...Happy to Light lamps @ lotus feet

Ritual of lighting ghee lamps

One should light a lamp using ghee (clarified butter) because when burned, frequencies emanating from it are more subtle than those emitted by burning oil or wax. Ghee can attract sattvik (pure) frequencies from as far as heaven while oil can attract frequencies from a distance of only one-meter.

The ghee lamp symbolizes the spiritual emotion, ‘I will be (spiritually) enlightened and (spiritually) enlighten others as well’. The ghee lamp burns to spread light. One can pray for kindling the light (spiritual yearning) within us and for the ability to spread the light (Spirituality) to others.

What is the significance of offering lotus flowers, tulsi leaves, and sheera or kheer as prasad (holy sacrament) ?

Flowers have different colors. Those colors are able to attract Pavitrakas (subtle particles) of different deities. In this case, Lord Krishna being an incarnation of Lord Vishnu is attracted most by white lotuses and Tulsi (holy basil, occimum sanctum) leaves.
Prasad (holy sacrament) contains the pure particles (pavitrakas) of a particular deity. In the case of Lord Krishna, Kheer (a sweet dish made from milk, sugar and rice/vermicelli) or sheera (a sweet dish made from semolina, ghee and sugar) are offered.