That's one way of doing it, but I've got an easier way; just follow my advice.
According to Bobbi Brown, your most flattering lip shade is only one or two shades darker than your natural lip colour. It's a fail-safe option for daytime if you think other colours will look too dark or bright.
Reds look great on everyone, you just need to know which shade to choose. For pink undertones, cherry red is a winner. If you're olive-toned, bright pillar-box red will contrast well.
When you have very light skin, darker colours look harsh and childish on your face. You suit light hues like nudes, pinks and apricot/peach. If you have brown hair, you may find that slightly darker shades will also suit you, as well as some shades of brown or coral. Cool reds will downplay any ruddiness in your skin.
If your skin is pretty tanned or you have a mixed race background, you can opt for darker colours than our fair-skinned friends. Mauve, burgundies, berry colours, darker browns and roses really work for you. If you're feeling adventurous, try a purple.
This skin colour is really versatile and it enables you to wear the darkest and brightest colours on the spectrum. Deep plums, reds and browns work really well, but if you really want to wow everyone, you could go for brights and even neons.
One last tip?
Warm lip shades compliment warm skin tones, and vice versa.