Step 1: Research!!!
Here is some honest advice: ONLY WORK AS HARD AS YOU HAVE TO!!!! Many state schools are great and practical choices for state residents: they are inexpensive, local and a great way to find what you want to do for a living without spending much cash. If you do not have the means to go to school out of state, don't worry about it. Just don't work super hard to get into a school that you can't afford and then end up going to a state school and resenting others who didn't do as much work as you.
Go to prospective school's website and
1. Find out what classes they expect you to take (standard, honors, AP)
2. Find out what standardized test scores they expect (SAT, SAT II and ACT)
3. Find out what they value- Are they focused on sustainable living for the near future and a cleaner America? Or do they specialize in bringing finer arts to life? This will help you shape your high school schedule as well as extracurriculars, and also tell you what to emphasize in the admissions process.
NOTE: If you end up taking more challenging classes then you need to, try not to worry about it. Education will come back and benefit you even if the result is not immediately apparent.