Hi all,
The things that really increase the performance of a mobile build that I found until now are below.
But before start, I should add this. "DON’T let any gameobject (which has complex components on it) showing in Editor Inspector before pressing the Play button. Because it may cause unbelievingly slow performance that you couldn’t even solve the reason. Editor try’s to update its information in Play mode and honestly sucks to do it.
Could you add yours, please?
1- Instead of Mono using IL2CPP as compiler and Use Incremental GC
3- Fixed DPI
4- Just having OpenGLES3 and usage of Linear as Color Space, on the otherhand if you don’t check “Auto Graphics API” game may crash in some devices and you really really don’t want it
5- Being carefull with Layer interaction for Physics calculations
and also low Default solver iterations.
6- Usage of a higher value for Fixed time steps (instead of 0.02)
7- Baked Lightning, being careful with Shadow distance and/or completely ignore shadows
8- Camera Culling.
9- Sacrificing Post Processing and Anti-Alising 
:(:(
10- Texture compression ASTC
11- 2k bitrate 15 FPS videos
12- Choosing shader. Yes Unlit is very performancy but it is also under my quality level. But with a right approach starting from the artist who makes the materials it can be a great choice.
13- GPU instancing and get rid of specular highlight from material options. If it doesn’t mess your model
14- Mesh compressing. Be sure that rewrite enable is unchecked (unless you know what to do)
15- Texture Compressing and resizing (512 or lowest acceptable) and actually producing textures not so much bigger than their usage size in game.
16- Refactoring. After messing your game in the learning process with a lot of unnecessary stuff you put under assets folder, starting the project from the beginning with your new level of knowledge (if you dare 
)
17- A Magical Word: OnDemandRendering.renderFrameInterval = 3; The result is unbelievable… but be careful your videos my flicker in that case you should back it to 0.
18- Be sure to have right import settings for mp3 files. Example picture below messages.
19- If you don’t click something in UI be sure it is not “Raycast target”
20- The amazing “Enter play mode options” check box…
21- Just to increase working speed don’t forget to use Preset manager which gives you a huge time because instead of changing imported picture audio fbx etc. settings every time, you just change the default preset (the picture of the menu is at the picture following messages).
22- Usage of URP for mobile. For me it is inevitable because graphics are awesome and even post-processing is not needed.
23- Burst compiler, really increase the performance
and Constantly disturbing Unity team to make them aware that "Unity’s Android Performance could be much much much better, why don’t you also do some upgrades that other game engines do
