I got this from covers but I think it's a very good read.
Set yourself a five-bookie minimum for March Madness and baseball. I guarantee that if you’re currently using less than five outs, you’ll improve your results. A half point here, five cents there… it adds up quickly. Many people do not take advantage of alternate sportsbooks like CaribSports.com
A small bankroll is no excuse. If you think your bankroll is too small to spread out over five shops, what’s really going on is that your unit size is too big.
Having many bookies also protects against the unthinkable. Some bookies lay down. Even ones that are thought to be well-established have gone belly-up. Don’t put all your post-up money in one basket.
The claim that you don’t have time to check lines at five different spots is no excuse. Aside from local outs (and everyone needs a local or two) there are live and near-live odds pages all over the Internet that collect odds from many different books and compare them. Covers has a Live Odds page for every major sport. Investigate the books on those pages. See if any of them suit your needs. Read what posters say about them in the forums and make wise choices.
Lines are getting sharper all the time. This is a discussion for another column, but it boils down to the Internet and access to information. The line’s design is not to predict the final score, but to draw equal action on both sides. That’s all well and good, but as a secondary function, lines are getting better at predicting final scores too. Why? Because more bettors have more information thanks to the Internet. More games “land” than they used to.
With more games landing, getting that extra half-point is more important than ever. The more outs you have, the more likely you are that one of your outs will have the number you need.
More serious players shouldn’t stop at five outs. As long as you have safety and ease of wagering, 10 or 15 makes sense. At some point, the law of diminishing returns kicks in—but it’s at a number much higher than 5.
Get yourself more avenues to win. Nobody said making money at gambling was easy, but the more tools you have, the easier it gets.