Despite my pleas, at almost every workshop I teach, a student will arrive with a palette of paint turds. You might know what I mean--those hard, pea-sized blobs of paint that look like they were squeezed out a century ago. The problem with dried out blobs of paint is that it is incredibly hard to load up your brush with pigment, making your painting a likely candidate for the wimpy pile.
I always recommend that students buy tubes of paint instead of pans for the same reason.
Currently, my brand of choice is M. Graham, although I also use Qor, Stephen Quiller, and Daler Rowney. All good stuff. You can't really go wrong with any of the professional grades; I believe it's a matter of personal preference.
I arrange my colors on my palette from opaque/semi opaque/granulating (left side) to transparent and staining:
From bottom, right: Cadmium Red Light, Titanium White, Cadmium Orange, Cadmium Yellow Light, Sepia, Cobalt Teal, Cerulean Blue, Cobalt Blue, Ultramarine Blue, Neutral Tint, Burnt Sienna, Cobalt Violet (also use Mineral and Dioxazine Purple), Ultramarine Pink, Viridian Green, Permanent Green Light, Golden Green, Transparent Yellow, Raw Sienna, Gamboge, Maroon Perylene, Pyrrole Red Light, Quinacridone Rose, Permanent Rose, Quinacridone Violet, Phthalo Blue.
Yipes! It's scary to squirt a $7 tube of paint into your paint wells. The best way to ease into it is to top off your paints with a squirt of fresh paint each time and mix it with the old.