Vaikasi Visakam is said to be the day when Lord Muruga/Subramanya incarnated in this world with the mission of saving earth from demons like Soorapadman.
Aadi Krithigai is a day auspicious for Lord Muruga. This year it falls on July 20. Karthikeya or Muruga is the second son of Lord Shiva and Mother Parvathi. Interesting and inspiring are his birth and feats, which are elaborately described in the Skanda Purana.
One should never go to the temple empty handed. You should take some offerings like Coconut, Fruits, Flowers or Camphor.
When adjusting the thread in lamps in a temple, your fingers will come in to contact with the oil of the lamp. One should never rub that oil on the head.