Don't think that the way of creating an account here does matter. You can immediately tag only your own pictures, which were not yet approved. In all other cases you can recommend them. Recommended tags need to be approved by a moderator before they will be published.
What is a basic tag set? 1) The title of the manufacturer (of anime, manga or game) or “original” tag if the picture is an artist’s work of authorship. 2) Names of characters. 3) The name of the author. 4) Gender. 5) The color of eyes and hair color. 6) Hair length. 7) The basic clothing elements. 8) The basic background elements.
Looking at how other similar pictures are tagged might also help.