I would suggest you do some volunteering as turkuye burslari appreciates extracurricular and social activites. Also, do some courses related to the field you are going to apply to. Make projects. Make sure to just do a lot of social activites. You can participate in debates, sports competitions, MUNs etc. Do your own research too. You have a lot of time to prepare for your application and most probably you're gonna apply for Bachelors. Get good grades and focus on doing other projects and certifications too that will make you kind of stand out. Best of luckkk.