Recently I built a Yidris deck. My deck was based around Eldrazi, since there's only 1 white Eldrazi card.
One thing I always ask is what is the theme of my deck? It looks like you are going for a graveyard deck, with cards like
Vigor and Lazav, so I would advise looking for surveil cards. That way you can put cards into the graveyard quickly.
I would recommend taking out the
Llanowar Elf, despite how good the mana is, it's not something you'll want to pull late game. Perhaps add in more removal, such as
Naturalize or counterspells. Maybe some bounce spells like
Capsize or
Boomerang that would allow you remove threats your opponent puts down.
As for lands, I might recommend swapping out some of the ETB tapped lands and go to basic lands. Then throw in a
Sword of the Animist so you can get a land just for attacking.
Aetherflux Reservoir is a great card, but I don't see much life-gaining in your deck.
Also, I love Double strike, but I think that would go better in a Saskia deck where you
deal damage to many opponents.
Hope this helps.