Design studio instructors, above all else, want their students to develop good process. If an instructor gives a good grade to what appears to you to be a poor project, it is probably because the student has demonstrated good process. Likewise, you may see an apparently good project receive a mediocre grade.Why? Because a project doesn't deserve a good grade if the process that led to it was sloppy, ill-structured, or the result of hit-and miss good luck.
101 things I learned in architecture school