trick of the trade

trick of the trade  {n. phr.},  {usually in plural},  {informal}

1. A piece of expert knowledge; a smart, quick, or skillful way of working at a trade or job.

Mr. Olson spent years learning the tricks of the trade as a carpenter.

Any one can learn how to hang wallpaper, but only an expert can show you the tricks of the trade.

2. A smart and sometimes tricky or dishonest way of doing something in order to succeed or win.