Do not just depend on the bookmaker. Take into consideration also the public bias because bookmakers might depend on them too much. Sometimes bookmakers adjust lines based on where money is going not really based on true probability. With these in mind, you can score a few consistent payouts. It is not just about choosing the winner but taking advantage of the odds presented.
Taking sport bets as an example, there's a way we can get to outsmart the bookmaker when we are considering for the odds given on the match selection we made, if we have more better understanding of how we could circumvent the situation for our own good, it's going to be a better experience on us because they could actually be wrong sometimes and we take advantage of playing games the probability of winning or losing is high in opposite direction to what the bookmaker expect for giving odds, in so doing, we are going to take advantage and this is also if we are the type that often gambles and also learnt how to pay attention.