This deck is pretty good at changing gears. You usually go for the bazaar/survival hands, but depending on who you are facing, black lotus + vengevine turn 1 is enough having disruption in hand to stop what your opponent is doing.
If you got no cards in hand, bazaar on upkeep to mill yourself for 2 is usually worth doing. Also, if you have bazaar and have only 1 bad card for the turn, wait for the other turn to be able to activate bazaar and chose the best out of the 4 cards you will have at your disposal.
You have force of will and mental misstep, but you should use your forces will a lot of caution. By that I mean, try to analyze if the play you are trying to stop will make you lose the game, and what can happen if you let that one resolve. I say that because there are some counter-heavy decks that (almost) always want to counter good spells. But your forces are usually there for great spells.
Leovold is ridiculous. I've had some cases where it literally won the game by itself. Like, you're behind getting hit and then all of a sudden your opponents can't profitably cast spells. It's awesome against blue decks in general.
Think a lot about clock and disruption. All the time you have to calculate what is your clock against your opponent, and how your actions will change it. This is kinda basic with magic in general, but there are really relevant decisions on that matter with this deck than with any other I've played, so watch out for that. Things like, against PO or other blue combo deck you can deploy leovold and win in 2 turns after this or combo off and win in 1.
This deck is aggro-control-combo. Know your opponents and read the gamestate, so that you know how it's best to act against it.
You usually can't race combo decks. It's usually better to search for more disruptive hands than go with no disruption (leovold/lavinia are disruption). BUT you sometimes win on turn 2. If you have a hand like bazaar, hollow, rootwalue and 2 vengevine, you should obviously go for it. Even though vintage is busted, I think most of the times winning on turn 2 with no disruption is enough.
Also, this deck takes some time and effort until it brings you some results. It took me a lot of time to figure it out and start getting positive EV out of MTGO leagues, as I imagine that took other people here too. But the journey is pretty cool as well.
And most of all: don't get discouraged when you get "vintaged". Variance has a pretty big roll in vintage, and even though your skills will determine in the long run if you are successful, and decisions matter A LOT, sometimes your opponent will have turn 1 mentor with tons of stuff, or big outcomes, trinisphere, recall+snap+lotus+fow+waste+.... But it happens. And vintage has the best public I've seen on MTGO in regards of not getting salty against lucky opponents, because we can't blame people for how lucky they or we are.