I've been playing magic on and off for a long time, but as far as I can remember this is my first time messing around with white and green together. Any thoughts and constructive criticism would be appreciated. This deck hasn't been tweaked yet either. Thanks!

Lands:

2 Blighted Steppe
2 Blighted Woodland
2 Blossoming Sands
1 Canopy Vista
6 Forest
6 Plains
1 Selesnya Sanctuary

Plainswalkers:

2 Ajani, Mentor of Heroes
2 Elspeth, Sun's Champion
2 Garruk Wildspeaker

Creatures:

2 Captain of the Watch
1 Darien, King of Kjeldor
2 Guardian Shield-Bearer
2 Joraga Auxiliary
2 Nyxborn Shieldmate
2 Precinct Captain
2 Preeminent Captain
2 Rhox Maulers
2 Veteran Warleader

Spells:

4 Launch the Fleet
2 Naturalize
4 Sylvan Bounty
3 Raise the Alarm
2 Oath of Nissa
2 Call the Gatewatch

When I saw your post I said to myself "Hey I have a G/W creature pump deck that I haven't played in a long time that was pretty powerful."
And it was. However when I pulled it out to look through it I realized that it was extremely inconsistent and needs a lot of modification. Lol. So thanks for drawing my attention to that.
Anyway.
I like your deck but there are a few things I would change:
-Since its only a two color deck I feel Oath of Nissa is unnecessary.
-As for creatures you the only spot you don't have filled is a 4-drop. I would consider replacing the Oath's for a couple "Dawnbringer Charioteers"
-As for your land, Selesnya Sanctuary requires you to return a land from the battlefield. If you have some lands that have a nice trigger when they enter the battlefield that is useful but otherwise I would swap it out for an "Evolving Wilds". And of course if you can replace your two Blossoming Sands with more Canopy Vista that would probably be a good idea too.
That is all. The rest seems like it probably works well together.

Last thing. When posting for deck reviews, instead of listing out the deck contents: build a deck on Deckbox and provide a link to it. This allows us to see more of the card details if we can't remember them off the top of our head. :)

Happy Playing