Become an expert in what you bet on. For example, if you watch NBA games everyday, you probably have a good idea which teams have an advantage at any given time.
This is a good piece of advice. Thanks! I am new to betting. I made only several bets. Honestly, I used to think that the only thing I need is a reliable website. But having found a list of sports betting sites (suggested by the experienced people), I understood that I also need to be aware of the latest events in the kind of sports I'm going to wager on. So, I'm currently reading about basketball and watching games.