When I colour my candles and am not making custom, I usually go with what the original scent "looks like", like red for watermelon, brown for chocolate, purple for lavender etc., so I guess what you're after is colours for "types" like Passionate Kisses and things. Personally I'd think of what kind of theme my candle is going to have, is it sexy, is it relaxing, is it fresh? And then colour accordingly. Red/black works well for sexy, soft pinks, blues and purples work well for relaxing, bright greens and ivory for fresh, that sort of thing. In the end, everyone's going to hav a different opinion so do what works for you