I work with candles sometimes, but to me, the candle isn't the Deity, it's a tool to help me focus my intention.
Colors have certain psychological associations, like blue is cooling and healing, green is manifestation, red is vibrant energy, etc. So, depending on what I'm trying to do, I might pick a certain color to help me keep a certain mental and emotional focus. I use the burning flame as a visual aid for meditation, and I also view the smoke as being a vehicle to help carry my prayers to the Goddess. A lot of religions burn candles and incense for the same reason.
What I call doing a ritual some people call prayer, and some people call it casting a spell. I've run into people who get that it's the same thing but different, and I've met people who utterly invalidate my spiritual practices because they are different from theirs. I'm sure you've met both kinds of folks too.
