New to poker? Play your first hands, with a coach at every decision. Practice points only.
Signals and tests
Believe signals that are costly to fake, and use tests whose answers differ by who is answering.
You were part-way through this lesson, at step 1 of 6.
A signal tells you something when it would be costly to send falsely. A raise from a player who almost never raises is a strong signal; the same raise from a player who raises every hand says little. Every bet also works as a test: different hands answer it differently, so a call or a fold tells you something. Bet for value or as a bluff, and read the answer as a bonus, not the reason.