This document discusses OPL best practices and includes the following sections: calling OPL from outside programs like Excel, Matlab, Python, and R; modeling tricks within OPL like using piecewise linear functions and decision variables as indices; practical tricks within OPL like displaying 2D objects, exporting to CSV files, and calculating the Cartesian product; decomposition techniques; and specific examples. The document is intended as a supplement to documentation and trainings, and the author welcomes feedback to improve it. Examples referenced are available on the author's LinkedIn page.