Lip colour is personal. The shade that looks effortless on one person may feel too bold or too muted on another, so start with the colours you enjoy wearing rather than a strict set of rules.
Look at the colours you already love
Notice whether your everyday wardrobe leans warm, cool, neutral or mixed. Peach, coral and brick often feel warm; rose, berry and blue-red shades can feel cooler; beige rose and balanced mauves can be versatile neutrals. These are useful starting points, not fixed rules.
Choose a finish for the occasion
Cream and satin finishes are often easy to refresh through the day. Matte formulas can offer a more defined look, while gloss adds shine and makes a simple makeup look feel more dressed up. Comfort matters as much as the finish—especially if you plan to wear the colour for hours.
Test in natural light
Apply a little colour and look at it near a window if possible. Check how it looks next to your natural lip colour, and give it a few minutes to settle. A shade should make you feel comfortable rather than force you to change your whole makeup routine.
When in doubt, a rose or muted nude can be a useful first shade to explore; from there, try a brighter or deeper version of the colour family that already feels like you.