What a recession changes for ordinary businesses before people notice it

When commentators say the economy has entered a recession, it sounds like everyone receives the news simultaneously. But a neighborhood café, a plumbing business and a software firm probably feel a slowdown at very different times. Does it start with customers postponing purchases, businesses cutting orders, lenders tightening credit, or a mix that feeds back on itself? I'd like a plain explanation of the sequence without treating every recession as identical.