Why is this important? If you’re only looking for a fun sweat, it does not matter at all. But, if you’re looking to be a winner and making money long-term is important, then this becomes critical. For those of you profit-minded bettors, make sure that you are only betting on the prop bets that require quite a bit of skill. These bets will be the ones that your knowledge, research, and expertise will help you win over the long run.

The number-one key to success here (as it is with any type of sports bet) is understanding what value is and knowing when and how to take advantage of it. Value, in a nutshell, is finding sports bets that are paying you at a better rate than you think they should. If you place enough of these bets to overcome variance, you’re going to be a long-term winner.
Identify the type of line you are looking at. All online sports books offer you the chance to have your lines in an "American" or "Money line" version. If I were you, I would use this as my standard. An "American" line uses either a + or - before a number to indicate odds. So a -120 and a +120 are two very different odds on a team… I will explain the differences shortly. Two other less common variations exist: decimal odds and fractional odds.
There is no such thing as a half point in sports, but there is in sports betting!  The half point ensures that a side will win and that the match will not end in a push, where the spread equals the actual difference in points between the two teams.  In a push all bettors get their money back, which is no good for the oddsmaker!  Half points also give oddsmakers more control over lines, allowing them to set more specific values.

If the bookmaker was only confident enough to give Seattle a field goal’s lead on the Patriots, it was clearly going to be a tight game. Oddsmakers aren’t often that wrong about flagship games like the Super Bowl. All things being equal, it’s likely the betting public would have taken the Seahawks to win the game and have been done with it. But throw in the point spread that gave the Patriots 2.5 points, and the proposition seems more equal.
This highlights a notable advantage of the moneyline wager. You get to control, to some extent, the risk versus reward. For example, you might be quite certain that the Cardinals are going to win this game, but not convinced that they're going to cover the spread. So a moneyline wager is the safe option. There's less money to be made, but less chance of losing. On the other hand, you might think that the Packers are going to cause an upset. Rather than betting on them to cover the spread, you can bet on them to win outright. There's less chance of winning such a wager, but the potential returns are much greater.

Especially in major tournaments, some sports books offer odds on unusual golf propositions, such as the over/under on the winning score, the over/under on the lowest round by any golfer or the over/under on the finishing position by a particular golfer. For example, the over/under on Woods' finishing position may be 3 1/2. If he finishes first, second or third in the tournament, the "under" wins; if he finishes fourth or worse, the "over" tickets cash.
You may have heard the term “covering the spread” or the phrase “betting against the spread.” This means that if the favorite team wins an event with the point spread taken into account or that the underdog team wins with additional points, they have covered the spread. If the Packers win that game by more than 7 points, they have covered the spread.