Hey mate! I have some suggestions for your deck! I hope to enlighten you and help you come up with a stronger G/B elf deck!
Land: (20 total)
X Forest
X Swamp
-4 Woodland Cemetery
+4 Gilt-Leaf Palace
+1 Urborg, Tomb of Yawgmoth
-1 Pendelhaven
Put in 14 Lands in Deck and figure out the Green and Black cards to figure out the X number of forest and swamp.
https://www.eweezy.com/2012/05/mtg-land-calculator.htmlSpells: (10 total)
-1 Death Cloud (This is cool.... but by the time you can actually play it (THREE SWAMPS) it won't really be all that useful except for the loss of life.)
+1 Elvish Promenade
-1 Rise of the Dark Realms (This is cute, but no. You don't kill enough to make the most of this card. Plus it is expensive.)
-2 Haunting Echoes (Not really relevant to an elf deck.)
+1 Plague Wind (With Elvish Archdruid and two swamps you'll be able to probably win immediately after casting this.... it depends though.)
-2 Genesis Wave (Too strict on forest mana to play consistently. This is an extremely late game card and I would venture to say elf decks are meant to be more agressive.)
+4 Duress (Control baby!)
Artifacts: (2 total)
+1 Coat of Arms
-1 Door of Destinies (You are sort of spell heavy)
-1 Staff of Domination (You build decks around this card. You can get a turn two win with elves and this card on monogreen, but you are going for G/B.)
Creatures: (28 total)
+4 Llanowar Elves (...this is absolutely mandatory for any and all elf decks.)
+2 Jagged-Scar Archers (Or swap this out for 4 Heedless One's...)
-2 Bramblewood Paragon
-2 Deathrite Shaman
+2 Fauna Shaman
+/- 0 Elvish Archdruid (Consider swapping him out for Priest of Titania.... whatever your heart desires.)
-1 Ezuri, Renegade Leader (Legendary's are cool... but his abilities are not relevant to this deck.)
+1 Jarad, Golgari Lich Lord (Let's focus the deck around this guy. Use Fauna Shaman to tuter this mate then Jagged-Scar or Heedless to do a lot of damage.)
-2 Joiner Adept (No need with only two colors.)
-3 Jorago Treespeaker (We do not need the mana acceleration from this guy.)
-3 Joraga Warcaller
-1 Lys Alana Bowmaster (Depends on the format. I am assuming this is casual with your mates. If you just gain a ton of life with essence warden you might be able to bypass the flyer damage.)
+1 Nullmage Shepherd (good for removal.)
+3 Essence Wadren (Life!)
+2 Imperious Perfect
-1 Rhys the Exiled (Essence Warden covers you.)
-1 Rhys the Redeemed (Imperious perfect covers you.)
-2 Talara's Battalion (Since this is not a monogreen deck you may have issues of getting it onto the field.)
Planeswalker: (0)
-1 Nissa Revane
This should help make your deck a little tighter. You could probably do without the plague winds but see how these modifications treat ya!