You are helping someone set up ChatGPT on a free account for the first time. They want the least effort for the biggest improvement in the answers they get. What do you tell them to do first?

The principle — the highest-value first move is the one that improves every answer, costs nothing, and does not depend on work the person has not done yet. Judged that way, the four candidates separate cleanly.

Why the key is correct — custom instructions let you share anything you would like ChatGPT to consider in its response, and OpenAI states they are applied immediately to all chats. Three things make this the right first step specifically. It is free and available on all plans on web, desktop, iOS and Android, so a free account is not excluded. It applies everywhere at once rather than to one body of work. And it addresses the thing that most limits a beginner's results, which is that the assistant does not know who is asking or what a good answer would look like — OpenAI's own prompting guidance is to be clear and specific and to provide enough context, and custom instructions are that guidance made permanent instead of retyped. The fields cap at 1,500 characters, which is the right size for a standing brief.

Why the others are wrong — upgrading addresses capacity, which is not the constraint a new user is under, and it is the only answer that costs money. Turning memory off trades away a benefit to prevent a problem that has not happened, and it is unnecessary because the memory summary can be read and corrected at any time. Creating projects builds structure ahead of the work, when projects pay off from returning to the same material repeatedly, which has not started yet.

Remember this — when ranking setup advice, ask three questions in order: does it apply to everything, does it cost anything, and does it depend on work that already exists. Custom instructions win on all three, which is why they are the standard first recommendation. Projects and memory both become valuable later, once there is actual work for them to organise.

Sources — OpenAI's ChatGPT Custom Instructions and prompt engineering best practices articles.