each case is different, there is no General Efficient Methods, there is so many factors: - What's Your niche - What's Your Budget - Do you have talent ? are you creative? with no details about your project nobody can tell you whats working and what's not..
Niche is highly important.. there are various techniques in marketing a site... This is one of the first things I consider before determining which methods I should use when marketing my site. If you want to start with the basics: try social bookmarking...
CPC advertising is the most efficient, but often the least cost effective. How long is a piece of string?