Picks come in different shapes, sizes, thicknesses, colors and materials. The choice of a pick is a personal one. Preferences will most likely change over time. A good strategy for a beginner is to by an assortment of picks and let them experiment. A few general guidelines are probably in order. Thin picks are better for strumming chords. Medium to heavy picks are better for picking single note melodies. A medium pick is a good starting point. Students with small hands may do better with the small "jazz" picks. I don't recommend the big triangle picks.