My first EDH deck (need help)

{"ops":[{"insert":"Regarding the mana base: you have too many lands that enter tapped, that's slowing you down a lot. Myriad Landscape in particular is a very slow card and not worth the color fixing it provides.\n\nSome of your top end creatures seem a little clunky: "},{"insert":{"card-link":"Eternal Skylord"}},{"insert":" and "},{"insert":{"card-link":"Halo-Charged Skaab"}},{"insert":" don't really do enough to justify being a five drop.\n\nI'd also add a couple of sacrifice outlets: "},{"insert":{"card-link":"Braids, Arisen Nightmare"}},{"insert":" is a great card draw engine, "},{"insert":{"card-link":"Phyrexian Altar"}},{"insert":" for added ramp, "},{"insert":{"card-link":"Carrion Feeder"}},{"insert":" gets big quickly. "},{"insert":{"card-link":"Gravecrawler"}},{"insert":" and "},{"insert":{"card-link":"Stitcher's Supplier"}},{"insert":" are good additions as sacrifice fodder and help you lower the curve a little.\n\nI'd trim the big high end sorceries like "},{"insert":{"card-link":"Necromantic Selection"}},{"insert":" and "},{"insert":{"card-link":"Necrotic Hex"}},{"insert":" - they are way too expensive for their value. Just go for a normal board wipe instead. A good rule of thumb for any card that cost 6+ mana is that it needs to be able to win you the game on the spot to be worth inclusion. Those don't.\n\nAlso, I'd put some more thought into what your plan is for closing out game. Do you want to end games by draining people out with "},{"insert":{"card-link":"Gray Merchant of Asphodel"}},{"insert":"? If so, I'd lean harder into the reanimator/aristocrats package, with cards like "},{"insert":{"card-link":"Reanimate"}},{"insert":", "},{"insert":{"card-link":"Animate Dead"}},{"insert":", "},{"insert":{"card-link":"Phyrexian Reclamation"}},{"insert":" or "},{"insert":{"card-link":"Zulaport Cutthroat"}},{"insert":". Do you want to just run people over with a horde of zombies? Then focus the deck more towards zombie lords and token creation.\n\nOtherwise, as a first deck it's a lot better than many attempts I've seen. \"Underperforming\" is relative. The deck as stands is probably better than most precons, but too slow to compete against more optimized or high-power decks. If your playgroup typically runs decks around the precon level you shouldn't need to do too much. If they are running decks with lots of fast mana or cheap combos, then you'll need to put in a lot of effort to get this deck up to that level (and start running some degenerate combos yourself, such as "},{"insert":{"card-link":"Pitiless Plunderer"}},{"insert":" plus "},{"insert":{"card-link":"Gravecrawler"}},{"insert":").\n"}]}