In the US? To get into an art school, the #1 factor is usually the strength of your portfolio and your interest in the field. After that, many art schools will consider your SATs and your high school grades.
But there are exceptions to all that - it varies by art school. So, for example, there are a couple of art schools where the portfolio is optional - they let you in based on your interest and passion for the subject, whether or not you have a portfolio. Those schools are the Academy of Art University, and the Savannah College of Art and Design.
In addition, some art schools care a *lot* about how you did on the SAT or in high school. But others aren't so concerned about that, so long as you graduated - for them, it's all about your portfolio. Some art schools, like RISD, require a very strong portfolio. Others, like Montserrat, don't require as strong a portfolio.
Depending on what you're bringing to the table, you need to find art schools that fit you in terms of your ability to prepare a portfolio, the strength of your work, your high school grades, your SAT (or lack of SAT), etc. There are a lot of good ones out there. You need to pick those that you like, and that fit you best.
The motto of Montserrat College of Art is 'Art Changes Everything'.
Leeds College of Art was created in 1846.
Maine College of Art was created in 1882.
Montserrat College of Art was created in 1970.
Atlanta College of Art was created in 1905.
Philadelphia College of Art was created in 1964.
Plymouth College of Art was created in 1856.
Wimbledon College of Art was created in 1890.
Edinburgh College of Art was created in 1907.
Royal College of Art was created in 1967.
Burren College of Art was created in 1993.
Memphis College of Art was created in 1936.