There are two main methods of betting that players should learn as they're getting into the game: moneylines and point spreads. Focusing on the latter, here is a primer into the world of margins and point spread wagering.
The point spread is meant to make things a little more equal, in the sense that you assign a certain number of points to a team/side that isn't as strong as the one they're playing. In moneyline betting, all you have to do is pick a winner. However, in some sports where there is a clear mismatch – let’s say a big, established college football program versus a downtrodden small school – the outright outcome is very obvious. That’s where the point spread comes in. If the perceived better team has to win by, say, 20 points, that makes the decision much more challenging and the matchup on the field much fairer.
Straight bets are in fact the most common and most simple type of sports bet ever used. You make a straight bet when you wish to place a wager on single side of a game and to win it, you must correctly choose the team that will cover the spread or the total (Over/Under). Straight bets are also called "sides".
In general, when you make a straight bet you must pay 10% as a "service fee". This service fee is called the "juice" or "vig" and the amount charged may vary from one sportsbook to another. Browse through the betting sites, open an account on your favorite one, head over to check their lines and notice the juice they charge. Sometimes, you can find games at -105.
Another option to keep in mind is live betting, which refers to wagers you can place while the game is in progress.
These are the sports in which point spreads are more relevant. The best way to show you what a point spread is with an example, so let's take one from the NFL. The Super Bowl champion Denver Broncos might play a lower team like the Cleveland Browns, but the spread might favor the Broncos by seven points because they're better. That would read as the Broncos -7 while the Browns would be +7. This means the Broncos have to beat the Browns by more than seven points, while the Browns need to win outright or lose by less than seven in order to win. If the outcome lands exactly on seven points, that’s known as a push and the game is a tie (you get your money back). It works the exact same way in basketball.
Point spreads aren't as popular in these sports, but it's still possible to do it. Puck lines are for betting hockey and run lines are for betting baseball, but there is a standard line for both: 1.5. You'll see one team is either -1.5 as the favorite, or +1.5 as the underdog. What this means is, for the favorite, they have to win by more than 1.5 goals (by two), and the underdog has to lose by less than 1.5 goals or win outright. So they could lose by one and you would win. It is the same for run lines in baseball, and again, the line is usually 1.5 either way.
Asian handicaps are used in soccer, which means the chance for a draw is taking out of play. Take an example of Manchester United as the favorites against Liverpool. The Asian handicap is -1, which is basically Liverpool up 1-0. If you were to bet on Manchester United, they would need to win the game by two goals or more. If they win by one, you would tie. For Manchester United, you get a better payout if you win since you have a smaller window of victory. For Liverpool, it’s the opposite as you’re getting a bigger safety net (since they can lose by one and you won’t lose your wager if you bet on them).
Finally, the point spreads in tennis is all about how many games a player will win. So let's go with Serena Williams as the favorite over Maria Sharapova. Williams might be at -3.5 for this match, which means she has to win more games overall. If she wins something like, 6-4, 6-4, that means she wins 12 games to eight for Sharapova; the difference is four, so that means she wins. You don't see a lot of point-spread betting in tennis, but it spices things up a little bit when the moneyline odds get very large.