College admissions officers want to see that you can read and write at a college-ready level, which usually requires that you take four years of high school English. Even college programs that focus on technology or professional studies, such as nursing schools, need to see that you can read textbooks and write good papers.
Most colleges want to see that you take at least three years of history courses, including at least one year of American history and at least one year of European or world history. You could take an additional year or two of those subjects or study related fields, such as civics, political science, economics, sociology or geography.
Math requirements vary the most from school to school. Reputable liberal arts colleges generally require that you take at least three years of math, including algebra II and geometry. However, if you are applying to a humanities program, such as a school for the arts, or to two-year colleges, it might be enough to take only two years of math. On the other hand, if you are applying to science or technology programs, you will most likely need four years of math, including calculus.
It is difficult to get into college unless you have taken at least two years of science courses, including ones with laboratory work. Most students take at least one year of biology with a lab and one year of chemistry or a generalized science course with a lab component. More competitive colleges might expect to see three years of science on your transcript; the third year can be physics, environmental science, psychology or a more advanced biology or chemistry class. If you are applying to science or technology schools, you probably need four years of science, including advanced courses in biology, chemistry and physics.
Not all colleges require that you take a foreign language in high school, but many do. Most college-bound high school students take at least two years of a foreign language, and many will take four. If you take a full four years, you might reach a level of proficiency that will allow you to become exempt from your college's own foreign language requirements.