Checking errors from a series of function calls
Do your early returns properly, and there will be no more to tweak:

int Foo()
{
    int result;
    if((result = Init()))
        return result;
    if((result = SetTemperature( 30 )))
        return result;
    return SetVoltage( 5 );
}


Using the extra parentheses () around the assignment to suppress a compiler warning.

I don't check for expr != ERROR_SUCCESS because that's equivalent to expr in a boolean context.

If there are really a lot of those calls, consider investing in a preprocessor macro.
Don't forget to undefine it after use if the compilation unit is not at an end.
Also, many really don't like those.

#define OkOrReturn(a) do{int result = a; if(result) return result;}while(0)
#undef OkOrReturn