I'm in Minnesota where it's not legal so I use Underdog and Prize Picks where the state lets me do their prop parlays.
What I think I've noticed is I've been much more successful on the lesser, smaller stat categories than the popular ones.
In basketball that's assists and rebounds vs points and pts-reb-assists which are more popular. In football that's receptions, pass attempts and yes, touchdowns (which seems counter intuitive since they are so random but most props are higher/lower than 0.5) vs something like total yards.
There's nothing worse than when Chase has 9 catches for 71 yards when the prop is 7 catches for 72 yards.
I'm a complete amature to prop betting but that's one trend that seems to be relatively true even though it's counter intuitive.
Last thing, as mentioned, getting the cheapest line is imperative if you take it seriously. It's amazing how close these lines can get so you need to take advantage of every half point available.