Just apply to as many places as possible (tier 2, tier 3, tier 4 firms, especially boutique law firms), text HRs, reach out to partners on LinkedIn, cold email firms. Once you get an internship, grades don't matter anymore (except for CAM, and Saraf/Luthra sometimes). Focus on the internship program, if the firm has a presentation/ exit interview, prepare well for that. Work sincerely (especially with people higher up in the hierarchy), and try to get an idea about the firm's hiring scene by the 2nd/ 3rd week of internship. Don't fall prey to long term internships without assurance. Certain firms are infamous for that. At least get them to say that they are hiring for your batch and try to get a sense of the number of months they would want you to intern before committing, so that you don't end up interning at one place indefinitely.
Adding on to this, intern according to the job you want, do things diligently and remember each and everything you've done so that you are not caught off guard in interviews.
To get in law firm you have to somehow prove your credentials. Since u don't have very good cgpa and belongs to T3 college. I would suggest forget about rest of the things and try to build connections. You have to get a teir 3 or boutique law firm internship and not just of 1 month try to intern for long duration prefer it to be offline if not possible make it online. Here you have to perform good and then maybe they can convert it into assessment internship or they can also refer you to other law firms. All the best!
Your work and work ethic is. But look for teams and firms which are hiring or have vacancies.
You don't want to be interning with a team that aren't looking to hire
Do remember this is the only way for you, day zero/college placement is not an option because that is 90% marks