Start with:
a. Affordability. Run the net price calculator on each school’s web site to get an idea of whether it may be affordable. (But if your parents are divorced or separated, check whether the school requires both parents’ finances. If so, be sure to include both parents’ finances in the net price calculator, but be aware that many schools’ net price calculators are less accurate in this situation.)
b. Admissibility.
You need at least one safety that is affordable for sure and where you will be admitted to for sure (and admitted to your major if it admits by major). Start your list by finding your safety school(s).