Effective poker strategies revolve around the fact that each player does not know what other players' cards are. This reality implies several things. The first is that actions by opponents are most likely made according to educated guesses, mostly based on the probability of what cards other players are holding. Second is that one could win whatever one's hand consists of, if only one would act as to deceive other players into thinking that one is holding a better hand.
Two of these deceptive poker strategies are protection plays and bluffing, which are related to each other in form but differ in what they aim.
Bluffing may perhaps be the most famous poker strategy, but oftentimes misrepresented. Bluffing is done when a player plays aggressively even when they have hands that have no chance of winning or even improving. This means that the player tries to intimidate other players into folding through betting large amounts, or in other words acts as if the hand they are holding holds a high value (thus the term "bluff").
Protection plays are similar to bluffing in the sense that both poker strategies are executed through playing aggressively. The difference, however, lies in the strength of the hand. Protection plays are so called because it is done to protect a hand that is relatively strong, but not strong enough for slow playing, when there could be potential drawing hands from opponents.
For example, if a player holds a pair, then their hand is already strong. But if there is also a large probability that other players could have drawing hands (hands that could improve as the flop, turn, or river comes; as in a possible straight or flush), then intimidating them into folding would ensure a victory for the protective player.
Another difference between the poker strategy of bluffing and protection plays is its aim. Bluffing aims to make all opponents fold, for that is its only chance of winning. A showdown of hands would be disastrous for the bluffer. Protection plays, however, while still benefiting from an all-player-fold, just aims to reduce the opponents one would face during a showdown. A player holding a fragile hand would want to have minimal opponents to face during showdown, to increase the chances of holding a stronger hand.
These two plays, while seemingly easy to understand, are also easy to be executed poorly. One needs to remember that any poker strategy could not stand on its own. Along with executing protective plays and bluffs are several other strategies: building an effective table image, position, observation, deception, and of course, familiarity with the game itself. With ample knowledge and experience, one could perfectly execute these strategies, and win the pot.