High School Qualifications
Good grades in high school are only needed in more prestigious schools. But if you are willing to learn in private fashion schools, satisfactory passes will be fine. Important subjects to score in are your language skills (especially English) and art subjects.
Although most fashion schools judge their potential students based on portfolio, good grades in every subject reflects well on you. Students with good grades are usually viewed as attentive and dedicated.
Satisfactory Language Skills
You will need a good command of English to understand what your classes are about. Theory exams will usually be conducted in that language too, so having strong language skills will help you pull up your grades in these areas.
If you plan to take up fashion design courses in countries like Japan or Korea, you will need to take up language courses in Japanese or Korean as those will be your medium of instruction.
Most international fashion schools around the world conduct their lectures in English.
International businesses around the world use English too. Being good in English can also help you read many informative fashion books to guide you along the way. Having fluency in this language will definitely benefit you as a future fashion designer.
Your Design Portfolio
This is probably the toughest of the three requirements to build. Your portfolio will prove your capability to conceptualize, draw and design. It shows the skills your overall ability and potential as a designer. Portfolios that display good designs and those with assignments done for real companies will give you good entry opportunities.
To get started, read up as much as you can about fashion. Go online, search through libraries and talk to friends who know something about fashion. Or you can read my tutorial on how to build a fashion design portfolio.
Once you have designed around three or five pieces for your portfolio and assembled it together, send the soft copy to the schools of your choice and apply for your dream course!