This is my silly little high synergy, value, control deck that I think I'm decent enough to give a primer on at this point. The general idea you are trying to go in with this deck is just survive until you get a tempo advantage. Or even simpler, just survive. This deck is like an ant colony in that all the individual parts are kinda terrible but once you put them all together it's extremely hard to stop.
Generally you going to want to mulligan aggressively for 1, 2, and 3 cost cards that draw, give mana or remove enemy cards with exceptions against specific decks. Against always keep , against and other voltron style decks keep for , against keep and against keep .
For sites, mulligan to get as many different kinds of threshold possible generally. Although it sometimes is wise to keep single threshold sites if it works for curving out your hand. If you have a maybe keep that for early plays. Some matchups benefit greatly from site as well, being the best thing to keep against opponents that may have cemetery hate. is also great for aggro matchups. Notably if you get in your opening hand, only keep it if you think your opponent 1. won't have burn early on and 2. you have something that can put stuff in the cemetery early on i.e , or . Its best to think of as a spell rather than a land, don't always play it if there is any possibility you could die.
Early turns should be spent playing early value drops that fill up your cemetery or give card advantage like , and . If you hit a dead draw in the matchup is one of the best cards in the deck for filtering cards, like pitching as its only use to play from the cemetery once you get your opponent to death's door. Also on turn 3 into playing the again is like my favorite shit ever.
Once your opponent starts playing stuff, kill everything they play. Okay not everything, often times a big skill check with this deck is not figuring out how to kill something, its just should you. Threat evaluation is important. Often times you can get away with building up your board even more and just chump blocking whatever they throw in front of you, and then you get to piss them off by playing those cards again! Also always check to see if you can use your opponents genesis abilities and ordinary magics against them as and are not exclusive to your own cemetery. Although remember to always savor your life total, I've found its easy to get lost chump blocking or taking a bit of chip here and there and then you find yourself to far behind to catch up.
After you get back tempo its a pretty simple way of winning, just kill them with a thousand little dudes over many turns and kill all there stuff some more. Also just kinda wins games sometimes.
Other miscellaneous synergies that are important for the deck include not being banished after playing it from your cemetery, allowing you to trash it early on as it functionally is an extra card in hand. is never cast on yourself, always sacrifice a spellcaster with it. You can also sac if you really need those cards. Often is just there to smooth out you curve, getting a or for the next turn usually isn't bad. Remember when your opponent is searching your hand or deck. is one of the best cards in this deck as you get fetch it with and it prevents most ways an opponent will trying to kill you at death's door, allowing you to use your powered up ability for longer. Also it's one of the only ways to guarantee . is the best card in the deck and no one will talk shit on its name, as I said before it can ramp you even further, fix your draws with , and often it just wins me games as it sits in my cemetery with a to find . is a special addition as it functions really well with all the spellcasters in the deck. If you discard Vivien you can still play it from the cemetery to copy the genesis effects of all spellcasters in the realm. Also sometimes it just wins the game as long as your opponent doesn't remove it (which can be pretty funny against an ), playing two minions from the cemetery a turn is a lot better than one, and remember to draw/play a site with her!
This deck still struggles against decks that can slam down a powerful game ending threat each turn like water necro and is part of the reason I used to have and in my collection. Its gotten a little more even with the addition of 
cards that allow for efficient threat removal but its something I would consider adding if you expect a lot of necro. There are some cards I would considering taking out if you have other options or want to test the waters like as she is very threshold heavy early on, who has rarely ever come up in my games or as he is very threshold heavy and at the time of writing is like 90$ what the fuck.
Possible additions include everything in the maybeboard but I would mostly consider and as cemetery hate. , and for better fixing. as said before. and for mortal and voidwalk heavy decks respectively. Also , or if you want actual 4 drops. Also and for other good fixing.