Somehow I feel that Advanced+ member is still a bit elusive although the requirement is really simple. A bit too passive for the applicant since the applicant wouldn't even know whether he has been put up for nomination or whether the nomination is successful or not. Private rank application is at least much clearer. You made your application and if the application is rejected, you would know that there is something further to improve on.
Advanced+ is pretty simple, people just need to have either made a significant contribution to the forum through things like programming etc or through a decent amount of posts of an adequate quality (usually around 400-500).
and be generally "liked" if you rub people the wrong way they'll probably put off voting you in.