portfolio preperation for college

I want to apply to do an undergraduate BFA in interior design at either Pratt, Parsons, RISD or FIT but it is required as part of the application process you have to submit a portfolio. I dont have much art or design experience and therefore dont have a portfolio so was wondering if anyone knows of a good course or program that prepares students wanting to do design at college and helps students create a portfolio and teaches some design skills? Preferably in New York or generally the north east coast of America. I’ve applied for the Basics Interior Design program at New York School of Interior Design which is a 1 year course which pretty much does this kind of thing but want to know if there are any other options.