  We show that the structure constants of W-algebras can be grouped according
to the lowest (bosonic) spin(s) of the algebra. The structure constants in each
group are described by a unique formula, depending on a functional parameter
h(c) that is characteristic for each algebra. As examples we give the structure
constants C_{33}^4 and C_{44}^4 for the algebras of type W(2,3,4,...) (that
include the WA_{n-1}-algebras) and the structure constant C_{44}^4 for the
algebras of type W(2,4,...), especially for all the algebras WD_n, WB(0,n),
WB_n and WC_n. It also includes the bosonic projection of the super-Virasoro
algebra and a yet unexplained algebra of type W(2,4,6) found previously.
