There are several things that will make your TOK essay really stand out to an examiner:
Clarity
One of the key things examiners look for in a TOK essay is a clear structure and overall argument.
Your introduction is particularly important in this respect. In it, you must make the aim of your essay and how you will tackle the knowledge question clear. You need to make your thesis statement, briefly mention the AoK’s you will be using and define any key terms that will be featured.
Relevant AoK’s and WoK’s
Think about the relevancy of different WoK’s and AoK’s to your title and the possible connections they have to each other.
It’s important that you feel comfortable talking about the AoK’s you choose but remember you don’t need to be an expert in them. TOK essays are all about knowledge and how we acquire it, not one specific subject!
Balanced arguments
To achieve a high mark in a TOK essay, you need to show that you can counter opposing perspectives effectively. This means presenting strong counter arguments to each of your main points and then defending your ideas.
Use TOK terms and language
Essays which use sophisticated analytical language are looked upon favourably by markers, so include a decent amount of TOK terms. Make sure you use them appropriately though!
A more detailed version of these tips can be found in my TOK Essay Guides.