You want to make sure that when you are picking a team to place your bets on that you don't have your emotions making the decision for you. While you might be a fan of a certain team or player, that doesn't mean that that is a good place to put your money. If you want to make a profit, you have to look at the statistics.
Do your research on each team
You also want to do your research. This doesn't mean picking a handful of teams and researching them. You want to research every single team that you think could win. You want to study the players, find out if anyone has been recently replaced or added onto a team, and you want to make sure that no one is injured. If any of these things have happened to a team recently, make sure that you keep an eye on them for a few weeks before placing a bet. You never know how these changes are going to affect a team.
Watch a few past games before placing your bet on this specific team
Finally, before you make any kind of final decision, you want to make sure that you watch these teams actually play. If you are unable to watch a game that is currently happening, you should be able to go online and watch highlights and full games between two of the teams that you are looking to place bets on. This will help you decide which team really deserves your faith and money.