Please help: I’m going to my first tournament, and I need some tips

I’m going to participate in my first Judo competition as a white belt. The tournament has over 5,000 participants, making it the largest in my country, and my category ranges from white to green belts. I’m 1.93m tall and will be competing in the 73kg division.

My favorite technique is Harai Goshi/Osoto Gari with the Ippon Seoi grip, where I drop together with my opponent. Since my legs are very long, it usually fits well. However, if my opponent doesn’t allow me to control their right arm, I find myself without any effective attacks, relying only on counterattacks and a somewhat inconsistent Sumi Gaeshi.

With that in mind, could you give me general competition tips and share some fundamental things I need to know to perform well? Also, would you recommend any specific techniques for me?

Thank you very much in advance!