Bet sizing refers to the size you want to make your bet on any given street. The key to bet sizing is to structure it in a way to get your opponent to do what you want them to do in a particular situation. For example, if you have the nuts, it is tempting to go all-in. However, this is a terrible bet if you can not get called because you get no more value from your strong hand. You want to size so that a hand you have beat can call. Conversely, if you miss and are bluffing you want to choose a size where all but your opponent’s best hands have to fold.