Mock interviews are essential.
The point of a mock interview is to get an objective assessment of how you come across. They are usually unpleasant experiences (I hated them!) but if you don’t do them, you will miss out on crucial feedback. This is feedback that you cannot get in any other way.
How can you get a mock interview?
The good news is that both your university and your Inn will definitely offer them.
You should also feel free to ask any barrister(s) you know to conduct one, especially if you have been allocated any kind of mentor.
Mock interviews are a necessary evil. Just do them already.
Inner Temple mock interview scheme: https://www.innertemple.org.uk/education/bar-professional-training-course-bptc-students/student-schemes/
Middle Temple mock interview scheme: https://www.middletemple.org.uk/members/student-information-services/mock-pupillage-interview-scheme
Lincoln’s Inn mock interview scheme: https://www.lincolnsinn.org.uk/index.php/education/bptc-student-information/mentoring-scheme
For Gray’s Inn please ask the office.