Never skimp on the good stuff. Cheap materials make cheap artwork!
Put enough paint on your palette without retrenchment. Especially the colours you will use often, such as white, yellow ocher, cadmium red and burnt sienna. I often see students adding medium hoping to obtain more amount of paint. Always use the same order. The sequence you determine yourself, for example the darks left, white in the middle, and the lights on the right, or from dark to light with white left. Or the yellows and reds at the right and the blues and greens at the left side. It does not really matter as long as you always keep a fixed order. You must find your way blindly. (keep your kitchen organized!)
I am in favor of premixing some flesh colours. This palette is also called the closed or set palette. Take your time to premix this colours. For me preparation is fundamental. If, after premixing, there is no time enough left to start painting, put all mixtures on a tile that you save in an airtight container, and store it in the refrigerator until the next day.