Erica Meltzer English books (sat/act) are a must read - see if your town’s library has them.
Khan academy for the sat.
Have you taken subject tests? If not, look into that.
Focus on ‘meet need’ schools. With an act 28 you’re in the running everywhere (even Yale).
At many of these great, prestigious schools you’d get a full ride - Pomona, Colby, Carlton, Hamilton, Davidson, Haverford. Look into them as they’re pretty different - fill out the ‘request info’ form and read about them in the Disk Guide.
Google 'college solution 100% need colleges " - the July 2015 list is pretty extensive, not sure if there’s been a new list.
Use the Imfirst resources and the collegegreenlight resources.
Check out the diversity fly-ins.
Are you familiar with the common app?
You can familiarize yourself with it and start filling out the basic sections (demographics, family, education, activities) as those will roll over to the new school year. It closes soon though so familiarize yourself quickly - it returns August 1st.