There is a text field (Label="Staff Rating:") on the form for creating or editing a game node / page. Simply enter a number between 0-100 (%) and submit the form.

If a node is not yet rated (0%) you may give it a score without discussing it but you must create a discussion topic in the staff forum! We (staff) can discuss the rating and if necessary adjust the score to reflect the opinions of the Wii View Staff. Where people cannot come to a mutually acceptable agreement, we can average the different scores.
Staff Ratings Discussion Forum