Some other things to consider that haven't been mentioned. I don't know if any of these apply to tOSU (out of state tuition = no way in hell for me), but if you peruse their application information you can get a pretty good idea of what they're looking for.
- Letters of Recommendation.
Get 2-3 of them. Preferably from a teacher you liked, somebody higher in your HS's pecking order (counselor, VP, President...), and a manager at a part-time job or even a personal acquintance / friend of the family who could be considered a "role model".
- Legacy Student
Often times on college applications being a legacy student can give you a little bit of an edge. Check if any cousins, aunts, uncles, etc. ever attended Ohio State (Columbus or not) for so much as a day.
- Essay
If there is an option for one, DO IT. Taking the time to write even a 1 page essay shows that you are not only serious about them, and serious about academics, but serious enough about their University to put some real effort into it. Real-life experiences, and goals are good subjects to discuss.
I can't stress this enough. It's the same as doing a little research before a job interview -- if you already know a company's current projects, that shows you have real interest and you're not just the average hobo looking for money to pay the rent. Same here -- it shows you're not the average HS grad with a sense of entitlement going to college because it's what everyone else is doing.
- If at all possible, go to Community College or something else over the Summer. It is a MILLION times easier to get into Universities as a transfer student. This also applies if you've been denied entrance to Ohio State. Save some money, got to a local community college for 3 semesters or so (screw the AA degree -- it's worthless, just rack up enough credits to be considered a transfer), and then apply again. Take courses that will transfer easily (English 101, Psych101, History, a foreign language, etc.). You can figure out what courses to take by looking at Ohio State's general catalog and seeing what their "common core" requirements are. Most Universities are not picky about courses fitting that requirement. However, do NOT -- I repeat NOT -- take courses in the subject of your preferred major. Also avoid science classes. (Especially if Psych is part of Ohio State's natural sciences department -- or whatever the department with Physics, Chem, Bio, etc. is called)
Good Luck