These are some of the useful shortcuts for Android studio (Windows)
Double Shift - Search EveryWhere
Ctrl + Shift+A - quick command search
Ctrl +N - Find Class (capable of finding internall classes aswell)
Ctrl +Shift+N - Find File
Alt+F7 - Find Uses (To get the call hierarchy)
Ctrl+B - goto class definition.
Ctrl+LeftClick - goto to symbol(variable, method, class) definition/definition.
Ctrl+Alt+Left - Back
Ctrl+Alt+Right - Right
Shift+f6 - Refactor/Rename