To draw a candle and flame in colored pencil, you need a good reference, either drawing from life, or using a photograph. This is the reference photo for the example I'm going to draw. The 'tail' of a candle flame is usually a pale yellow, but it appears white to the camera because of its brightness. In my larger version, I can see a the slight band of blue at the bottom of the flame, where the combination of fuel and oxygen makes it burn very hot. The inner part of the flame, near the wick, has less oxygen and so is cooler.
I've chosen my Derwent Artists traditional colored pencils for this drawing, as I know they are popular, so many readers might have them. You'll get better results with a softer, denser pencil. Colors used are: white, ivory black, ultramarine, chocolate, deep cadmium, deep chrome, deep vermilion, and scarlet lake. You'll also need a kneadable eraser to lift any mistakes.