For math and numbers behind stuff etc, there's always D3planner and its simulation mode.
And if you just want to know "what stat should I go for on item X" you can always inspect the top people on the leaderboard (though keep in mind that that's for pushing the best rift, for the general rift speed running you probably want other priorities).
For more specific advice you need to be specific about a certain build. Since you play wizard, I'd recommend some of the Manald Heal builds. There's a lot of them (including math and explanation behind it) in this thread:
In the end, you can read as many stats as you want an theorycraft as much as you want, but nothing will be better than just playing the game - because your gear will improve, you'll get better gem levels, more paragon, and you'll learn how to play more efficiently.