How can i reduce GPU / LAG for a mobile game with a big map? any Tips please really one.

Hi,

I am trying to create a mobile game for Android and the game has a big map with lot foilages, basically a forest.
all Assets were used from free pacs and example contents from both market place and Learn Tab.
How can i reduce GPU / LAG for my mobile game with a big map? any Tips please really one.
To run the game smother and Faster.

Thanks in advance