All I can say is that if you're starting out and want to bet on sports, then shopping around for odds is an absolute necessity. This obviously requires you to not be banned with any of the bookies but it can make a huge difference to your bottom line picking up a few extra cents on each bet.

For instance lets say you have an approach/system on any sport that has average odds of $1.10 like you've hinted at Mike. 'Safer' bets focusing on favorites in sports, you had 1000 bets for the season with a 91.1% strike rate (911 winners) to make 2.1 units profit. Thats a great effort, you've beaten the bookie edge and made a small profit - but lets say you'd shopped around with 4 bookies and averaged odds of $1.12 on those same bets instead. Now you've made 20.3 units profit. 2 cents average better on each bet and you've boosted your profit on turnover by almost 2%.

If you've got the ability, then take the time to shop around for odds - it can make a mountain of difference. If I were going to pick a sport out to start on it would be AFL for the following reasons:

- Its not a global game, therefore less likely to have as many people data-mining it to try and make a profit on it
- The level of stats readily available are in their infancy compared to the big american sports. Thus if you can find a stat with an edge, you might get a good run out of it before others catch on.
- Team lists are huge and there are more players on the field then any other sport. This means its a team effort with hopefully less variance due to key players missing through injury or having poor games. Yes those players make a difference, but its not like Lebron James and Anthony Davis missing games for the Lakers.
- Scoring is high when compared to other sports. In rugby a field goal can make a huge difference, in soccer or ice hockey a single penalty can change a game. In AFL free kicks actually have very minimal impact on the outcome of a game (over time).

There's almost no other readily available sport to bet on that I've been able to find with these characteristics. Basketball is probably the next closest however it has a huge reliance on 1) Key players and 2) there are hundreds of thousands more people betting on it and reviewing it from a statistical standpoint.

To give you an idea, a person checked the performance of Houston when they went to particular cities and found there was some correlation between the performance of James Harden and whether that city had 'good' strip clubs. This then effected team performance.

I figure there are people out there who are waaaaaay smarter then me betting in the market and influencing the market to a point that the closer you get to game time, the betting 'market' is a solid indicator of the likelihood of the result. The big challenge is either using other peoples expertise (ratings) or finding an obscure stat or angle that gives you a slight profitable edge. Combine this with achieving higher odds and you'll be able to get some profit in your pockets.