You can use a variety of little molds to make your colored batches, I use a silicone cupcake mold for mine. Melting enough wax to fill it only about a third of the way full and generously adding color in the form of dye chips, blocks, powder or liquid dye (preferred) -- in other words much more dye than you would normally add to the wax if it was going to be a candle. You can judge this as you are working with it, but, for instance, adding about three to five drops of color for starters to make it concentrated. If you prefer to make it weaker for a lighter effect, then only add a drop or two. Remember, when you are using it, you will be sprinkling it in little flakes if you wish to achieve the speckled look.
Here's an example of a couple of colors I've been working with ... the dark color disk is the concentrated color and the lighter ones are an example of how using a small amount will turn out. Of course, these can also be used to color a candle with a solid color. To make speckles, you shave off or chip off little pieces. You can have a lot of fun mixing your own colors for your candles by making these ahead of time, and compared to using liquid dye, they aren't nearly as messy, giving you much more control on the amount of color you're using, as liquid dye is very easy to over color with ... just ask me how I know!
