To learn classical field theory, one must first grasp Lagrangian and Hamiltonian mechanics, along with partial differential equations and Fourier transforms. A solid understanding of vector calculus, including divergence, gradient, and curl, is essential, as well as basic distribution theory like the Dirac delta function. Renormalization group knowledge is not necessary for classical field theory, but is important in quantum field theory. Recommended resources include Griffiths' textbook for an introduction and Soper's "Classical Field Theory" for a broader perspective. Starting with a conventional electrodynamics book is advisable before tackling more advanced texts.