Just a few lines to explain about my palette and the suggestions I give you.
I don't really believe in set palettes, mainly because not only we don't want to all produce the same painting, but because each of us has tendencies that need to be "corrected " and therefore might need some colours rather than others.
If you think your painting is "chalky" remember to have some paints on your palette that migt be alternative to white to lighten your mixtures ( such as Lemon Yellow, Kings Blue Deep or Yellow Ochre), if you feel your colours are "dirty" beware of colours such as Raw Umber or Prussian Blue: if you find it very difficult to mix colours for skin tones perhaps you would find it easier to have more earthy colours at hand, etc.
The composition of the palette for me should be viewed in term of needs, adding colours as we go by because we feel we can't do without that particular paint.
Another element I would like to point out is that there IS a difference between makes. Lemon yellow is very different between Winsor & Newton and Michael Harding, and Cad. Red Deep Old Holland. is thicker and darker than Michael Harding's. It's not that one is superior to another ( although at times they are) is that its characteristics make it more or less suitable to a certain palette. KNOW THY PAINTS !
So: when you squeeze paint in the morning be aware not only of the actual colour ( always think if you can obtain that same colour from mixing first) but also of its identity. For example yellow ochre is opaque and thicker than a transparent dark yellow such as Indian Yellow. Which one do you need and why ?
Which ones are your favourite mixtures for skin tones?
Transparent oxide red is very similar in colour to burnt sienna but one is opaque the other transparent, which one do you need ? Are you going to mix it mainly with a transparent colour ? I find that opaque+transparent works well for me, for example I like purple madder + lemon yellow, white+ green gold+ cad red deep and so on.
If you don't know about the characteristics of a paint, look at the tube. Michael Harding's will say opaque, transparent, semi-opaque. Winsor and Newton have a little square, if it's white they are transparent, if it's black opaque, semi opaque have a white and a black triangle.