Thailand is a predominantly Buddhist country. There are many temples in the city and very often you encounter people praying and making offerings to Buddha (Wai Phra).
The offerings often consist of a candle, a flower (usually a lotus), a small square gold leaf and 3 incense sticks. The Buddhist holds the candle, flower and incense sticks with his hands in a wai gesture (hands pressed together like in prayer position) and circles around the chedi several times while reciting phrases from the Buddhist scriptures in their minds. The candle is then lit and placed in front of a Buddha statue, the flower placed in water and the incense sticks are lit and placed upright in sand while the Buddhist presses the golden leaf onto the Buddha statue.
You don’t need to be a Buddhist to do the Wai Phra and people will be happy to see you follow their culture and traditions.
A small note however: Don’t be tempted to smell the flowers or incense sticks when you do the offering. It is a gift to Buddha and not for your own benefit! It is believed that bad things can happen to your nose ;)