A full list of IPython built-in magic commands can be found here. Line magics are prefixed with a single % character and apply to a single line, whereas cell magics are prefixed with %% character and apply to the entire cell. These are the ones that I always use.

• Use the inline backend for matplotlib.

import matplotlib.pyplot as plt
%matplotlib inline

• Automatically reload modules before executing code.

%load_ext autoreload
%autoreload 2

• Print elapsed time.
  • Note: this is different from %timeit which calls the timeit module.

%time