Do you really want to make a lot of money, or just entertain yourself while mostly getting the best of it? If you do this for entertainment mainly, stick to dogs, and read occasionally. Talk to 5 of your friends, and if they all agree on one play, play the opposite.
If you are serious about this as a profession, you need certain skills before you even entertain this field. You need to be a wiz at Algebra (just your typical 8th grade algebra).
You need to be fluent in the betting terminology, and understand it. A good way to get started is with a book "Sharp Sports Betting" by Stanford Wong. There are other good books out there, but this is really a MUST book for beginners. Read it once, read the forums for a month, and re-read it.
If you have mastered algebra and terminology, and read the forums, you probably know enough to break even, or even make a small profit each season. If you know smart people, or shop well, you can do well each year with no more knowledge or experience.
If you want to take it to the next level, you might consider handicapping sports yourself. There are two main methodologies I've seen that work. The first is becoming an encyclopedia for that sport. If you are looking at an NFL matchup, and you know the strengths and weaknesses of each team, how many turnovers each has, and individual matchups, you gain an edge.
The other methodology (my primary one) is statistical analysis of a sport. Get a prob/stat textbook, and work your way through it, from front to back. You need to embrace the standard deviation. Not just know the definition, but have a feel for what it is in sports. You need to understand the difference between a mean, median and mode. A lot of this isn't rocket science, but the applications must be effortless.
A goldmine for smaller players (i.e. bank less than 100k) is the prop bet. Prop bets are basically free money. It's not unusual for a prop player to hold 25% of his action (he makes 20k in wagers, and he's up 5k). Most props can be analyzed with basic statistics (means, standard deviations, and poisson distributions) or discrete and combinatorial analysis.
As your bankroll grows, you'll find that statistics become more and more important. If you do the math long enough, you will find many opportunities. The question then is not "What is good?" but "How good is it?". Risk analysis and risk management become your primary time consumers as your bank grows (at least until it is so large, that you want to bet more than you are able to on any event).
Hope that helps.
