What some people mostly follow:
public variable: myVariable / variable
private variable: myvariable / my_variable
public function: myFunction / function
private function: myfunction / function
local variable: *same as private var
parameters: *same as private var
What i do:
public variable: myVariable / Variable
private variable: my_variable / variable
public function: myFunction / Function
private function: my_function / function
local variable: _myVariable / _Variable
parameters: _my_variable / _variable
One can easily tell what scope does variable/function has, by just looking at the name. all categories have distinct representation