What are you really good at?
What do you notice you have become particularly skilled at doing over the course of your PhD?
What topics do you know you’re particularly knowledgeable about?
How do you know you’re good? What’s your evidence?
How do you explain to yourself – and others – that you’re good at something?
Reflect and find the words to describe what you do well and how you know you do it well. Recognising that you are capable and knowledgeable is a helpful basis for feeling confident for your viva.
There really isn’t any other way to get to submission and the viva: you must be great at what you do. However, if you’re not feeling great, then reflect and find things you do well or things you know lots about.
If you already know that you’re capable, work to find words to tell yourself a good story about that so you really believe it ahead of your viva.