matplotlib allows you to set plot parameters via a param dict. Here's one such example

pyplot_set_params.py

import matplotlib.pyplot as plt

params = {'legend.fontsize': 'x-large',
          'figure.figsize':  (15, 15),
          'axes.labelsize':  'x-large',
          'axes.titlesize':  'x-large',
          'xtick.labelsize': 'x-large',
          'ytick.labelsize': 'x-large'}

plt.rcParams.update(params)