The first thing first is to make sure you risk your money on something you know a lot about, if you are a basketball fan it's safer to risk your money on basketball matches, don't look into football just because your labour next door is also football, many people are doing this that I know about, and once losses start happening they will go back to what they already know about, it's nothing but greed.
Sports bet requires some good follow up and analysis, this will increase your chances of winning, because you will be able to be a better predictor compare to someone who knows nothing about football and still decide to take risks of football matches, it's not a good gambling strategy.
I will also like to state the pure fact, you need to be careful what you are risking on gambling even as a good gambler that you are trying to be, those who place bets based on analysis still lose money, you will be wrong at times and you might be lucky at times, this is what gambling is all about, continue to risk only what you can afford to lose, this is what makes you a better gambler.
If you do really want to bet on sports and have good chance about it, it is indeed advisable to bet on a sports that you are most familiar and most comfortable with. The knowledge about the sports will give you an edge when choosing the best odds. Also, if you know the players very well, you can speculate their performance for that particular game, hence, understanding the odds provided by bookies and select which particular betting line will give you more edge.
You don't need to bet the major betting line of who will win or lose, but like for example in basketball - there are so many betting lines (actually one of the sports where you can find a long list of betting lines for a single match) that you can choose from, just consider every quarter of the game, their total scores, over/under, winning margin, etc. I believe in time, you will understand yourself more on which ones you are good at, and exhaust its potential to your advantage.