I bet the following ranked in order of which I make the most money...
NFL football, singles parlays, over/under I do it all. I've learned thru trial and error that moneyline is the best way to bet for me on the singles and parlays, but I will do large point teasers, and I keep ml parlays to 3 teams max. I usually bet big on them as well, if every punter has his specialty this ones mine. In the last 3 seasons including playoffs I can count one hand the number of losing weekends i've had. I don't stick to favorites I tend to look for value, wish football ran year round.
Tennis - I also do quite well in tennis, I do singles where I tend to go for dogs or if I see value in 1.5 plus. I wont touch lower than that unless its to sweeten up a parlay, I play parlays regularely and try to keep them small 3 and less but will once and a while go for some larger ones and back them with wta favorites just to bump up the values. I try not to look at my tennis bank week to week but more like quarterly as with large bets and betting dogs if I have a couple bad weeks in a row the bank can look ugly but then it only takes me a couple good days to make up a couple bad weeks. My styles not for everybody. I also have a bad habit of chasing losses in tennis by making parlays and backing them very heavy but on favorites to end the day well, its bit me a few times but more times than not it recoups a bit. Have to stop doing that lol but did it today
basketball, very rarely do singles, usually a parlay of 2 to 4 teams. I find that homecourt means more in bball than in any other sport so I will back what I believe are locks, I dont look for values most of the odds I get are pretty low as they are heavy favorites but with parlaying them they get a decent return. Dont really like this approach in tennis but works well in bball, tennis is just to iffy with possible injuries etc to bank a lot on a favorite but a team makes it safer.
Hockey and baseball I bet only during playoffs, terrible for betting regular season in my opinion. And only singles, and winners for each series.
boxing I dont trust, cricket I dont understand, soccer I bet terribly, and golf is not made for betting so I think thats about it.