I want Improve my mobile game graphics.
I create a game i want add hd graphics but Image size is too large what can i do reduce image size but graphics quality same?
What sort of models / graphics? You should be sure that your textures are compressed, You can lower resolution and use detail textures to add detail. What size textures are you using, and how many?
You can’t make the graphics look TOO good, but check out shadow gun by mad finger , thats basically the max you can do right now with android development with Unity
I would rather say modern combat 3 it has better graphics.
(IOS)
this is a very broad question, but for UI/2D use atlases, i.e. you’ll need a plugin like Toolkit 2D, for 3d textures on 3d objects use PVTC compression.
I am using texture size 5 mb. resolution 1024*768
but when i use PVTC compression image quality to very bad.
For me the best graphic for mobile right now is the deep space game from ea. Far better than madfinger’s.
how can i use HD Graphics for Mobile game.?
Post a screenshot of what it looks like now 
then we can give more advice.
I’m more concerned about ways to increase FPS on mobiles rather than graphics quality
That’s the same thing.
Wouldn’t they be inversely proportional?
Increasing FPS increases your visual quality since you can do more otherwise everyone’d be running around with raytraced engines.
But you could want to use it on non graphical things, like maybe AI?