Although there's no promise that if you take a certain combination of high school courses you'll get into any and every college you apply to, there's no question that you have to take the right courses in high school to be considered by most colleges.
Generally, it's strongly suggested that any high school student who hopes to attend college take four years of English and math and at least three years (preferably four) of science and history/government/sociology. Most colleges also require at least two years of a foreign language, but once again, more is better.
Regarding English classes, try to pick classes that let you do the most reading and writing. You want to demonstrate to the colleges you're eyeing that your high school English classes have taught you how to analyze and critique written materials and how to conduct research and write a paper.
Throughout your high school years, try to take the most challenging courses you can, including Advance Placement (AP) courses. Although your grades are very important, most colleges are a bit more forgiving of students who take the most demanding courses their high schools offer — to a college admissions office, a B+ in physics looks a lot better than an A- in general science. But also keep in mind your own limitations and be realistic: Don't sign up for courses you know you don't stand a chance of passing.
Career-related courses really don't add much to a high school transcript. If you think you might want to be an accountant when you grow up, then by all means take an accounting class as an elective. But the colleges you're applying to probably don't expect you to have all of your career goals mapped out when you're still in high school — having a well-rounded education in English, math, science, and history is most important.
Don't forget, the classes you take in high school and the grades you receive in them might be the most important factor colleges look to in applications, but it's not all. Say, for example, that a college is comparing two applicants with the exact same course load and GPA, but one student played a sport, was involved in one or two student clubs, and belonged to a community organization, while the other student wasn't involved in any extracurriculars. If the school can offer admission to only one of the two, guess which student will get the acceptance letter — the one who was involved in her school and community. Your scores on the SAT or ACT are also important.
Lastly, start thinking about college early in your high school career. Although it's true that some universities in particular like to see a "late bloomer," don't wait until your junior or senior year to get serious about your classes and your grades. Ideally, you should start to think about college and what you want to do with your life by the end of the eighth grade.