Poker tells are observable behaviors that can provide clues to a player's hand strength or intentions. They can be physical actions, betting patterns, verbal cues, or online behaviors. Reading tells is a complex skill that requires observation, analysis, and experience. Tells can vary greatly between individuals, and some players may intentionally fake tells to deceive their opponents. Understanding tells can improve hand-reading abilities and inform strategic decisions. While tells are not foolproof, they can provide valuable insights when combined with other information like player history and table dynamics.