Suggest you start with the metric tensor, g_{ij}, and then calculate the Christoffle symbols, \Gamma_{ijk}, to calculate the partial derivatives of the basis vectors with respect to the coordinates. See footnote on page 17 of attached document. See section 2.3.2 of same document on how to calculate the normalized basis vectors and their partial derivatives. For the coordinate systems you would be interested in the metric tensor is diagonal (orthogonal systems) but the basis vectors are not normalized.
For a spherical coordinate system the diagonal of the metric tensor (all other entries are zero) are -
g=[1, r ** 2, r ** 2 * sin(th) ** 2]