Unity3d optimization in one presentation

Let me just leave this here:
presentation

... and that links...

Practical Guide to Optimization for Mobiles (Unity Manual)
Optimizing Graphics Performance (Unity Manual)
Profiler (Unity Manual)

ShadowGun: Optimizing for Mobile Sample Level (Unity Blog)
“Fast Mobile Shaders” talk at SIGGRAPH 2011 (Unity Blog) - highly recommend to anyone who writes unity shaders
http://malideveloper.arm.com/
OpenGL ES 3.0 Developer Resources (Mali Developer Center) - now it's not widespread, but it seems to be very popular and effective in near future!
ASTC Texture Compression: ARM Pushes the Envelope in Graphics Technology (ARM Blogs)