Besides school things, do you have non-academic strengths?
One way to make your college application strong is by highlighting any extracurricular activities or volunteering experiences you have had that demonstrate leadership and initiative.
A track record is also a good record.
Demonstrating a history of good grades, even if not perfect scores, can help show colleges that you are capable of success in rigorous academic programs.
This shows that you are consistent academically and you place good, consistent effort throughout your program in the past - which you are ready and able to repeat again if you are offered admission.
It shows that you have a strong work ethic by participating in challenging courses.
Tell your story. You are more than your grades too.
Writing an engaging personal statement for the essay portion of your application will give admissions officers insight into who you are as a person beyond just test scores and grades; this could be influential in their decision-making process when admitting students with less than perfect marks.
Get people to back you up.
If possible, include letters of recommendation from teachers or mentors who can speak positively about the qualities they see within you such as dedication or hard work which may not necessarily be reflected in numerical measurements like GPA or standardized tests results.
Attend everything. Show up for it all.
Showing interest through campus visits and/or interviews also shows commitment on behalf of the applicant so should definitely be taken advantage off where available!
Some schools recognise a familiar face. If you show up (and a plus if you talk to the school people) during these functions, you are more likely to notice a neighbourly figure and build affinity to your application.
Pick colleges that values a holistic candidate.
Lastly it might also help to research universities that focus more heavily on holistic applications rather than just relying solely grade point averages - these institutions often take other factors such as life experience into consideration too which could benefit someone without top notch exam results.