Junior year is a great time to begin visiting colleges. Call or email the admissions office or check in the guidance office for "visitation days" especially for prospective students and their parents. Most of these days are on Saturdays, which are easier to schedule. Also try "virtual tours" online, which is a way to take a quick look at a campus. Spring break and summer are good times to take college road trips.
Also, begin compiling a list of your high school accomplishments, honors and awards, and community service for these applications. Scholarship searches online are free, so be cautious of scholarship services who contact students and claim to be able to help get money for college.
The junior year in high school is an important year in your academic career. Keep good study habits, take the ACT/SAT, begin browsing for schools. Get busy and don't procrastinate!