To lazy to form structure so here's a list of ideas:
1. Add fleecemane lions: their just solid 3/3s in green white colors
2. I don't like
sheltered aerie. The ramp it gives off is just not worth 3 mana. Try explosive vegitation or
elvish mystic.
Explosive vegetation costs one more, but it ramps out 2 lands and deck thins. In contrast,
elvish mystic give only one mana, it must be green, and can die to removal, but it hits the board turn one, letting your deck work much faster.
3.
Inspiring call: instant that let's you draw a card for each creature with a counter.
4.
Den protector is a solid card, but I don't see it having that much of an effect without its friend
deathmist raptor or decisively good card to get back.
5. Cut down on battle priest: life link is good, don't get me wrong, but it doesn't win games like trample or flying does. It will save your life in the aggro match up, but every game isn't aggro, so maybe move one or both into the side board?
6. Just cut enduring scale lord: the effect is good but it is still six mana with no evasion. I tried it in a green white deck like this and it just never worked for me. Maybe try the other dromoka. I
forget what he does exactly, but I know he's on;y a five cost and bolster's two whenever he attacks, so he's on theme.
7.
Gleam of authority: look it up. It can get real mean real fast in a deck like this.
8.
Evolving wilds if you run into trouble with your mana base, or some fancier lands like temples or fetches if you have them or are willing to get them. (Don't get them though. They are crazy expensive.)
8. Finally
Elite Scaleguard: I've never playe with him personally, but for five mana I'd expect at least a bigger creature.
9.
Citadel siege and hornet's nest. I forgot to mention those. They are versatile and good.
Hope this lazy list helps. Good luck.