10 ChatGPT Customization Tips 2025

OpenAI has reshaped ChatGPT over the past twelve months: the assistant now remembers you more deeply, speaks and sees natively through GPT-4o, and bundles long-running tasks inside Projects. Some 2024 best practices are obsolete, while new features earn a spot on every power-user checklist.

Quick Reference Guide

#	Feature	Where to Find It
1	Profile + Memory merge — saved facts and recent chats are now referenced together	Settings → Personalization → Memory
2	Custom Instructions (still 1,500 chars × 2) sync across all devices	Profile picture → Custom Instructions
3	Custom GPTs replace Plugins — build or install in the GPT Store	Explore GPTs → Create / Add
4	Advanced Voice & Vision with real-time translation	Message box → Voice icon
5	Model Picker & GPT-4o (GPT-4 retired)	Dropdown above chat
6	Structured output & tone controls	State format/tone in prompt or Instructions
7	Projects & Connectors for cited deep-work sessions	Sidebar → Projects
8	Granular privacy switches (history, memory, training)	Settings → Data Controls
9	Themes & layout (dark, compact, custom CSS via browser styles)	Settings → Theme
10	Global shortcuts, Siri/Action Button, desktop hotkeys	"?" icon → Shortcuts

1. Fine-Tune Your Profile and Memory

ChatGPT now works with a two-layer memory: explicit "Saved Memories" you approve and implicit insights from recent chats, enabling far richer personalisation. Free accounts receive a lightweight version, while Plus, Pro, and Enterprise get full recall.

Toggle either layer off or launch Temporary Chat to stay unremembered. You can always audit ChatGPT with "What do you remember about me?"

Pro tip: Use Memory for personal preferences and Custom Instructions for consistent output formatting.

2. Refine Custom Instructions

The twin Instruction boxes still cap at 1,500 characters each, but OpenAI now synchronises them across web, desktop, and mobile. Use them for evergreen guidance (tone, preferred output format, coding conventions), leaving dynamic facts to Memory.

If ChatGPT drifts, tweak the boxes rather than rewriting prompts each time.

Example Custom Instructions:

"Always respond in a professional but friendly tone"
"Format code examples with syntax highlighting"
"Provide step-by-step explanations for complex topics"

3. Build or Install Custom GPTs

OpenAI shuttered the Plugin Store in early 2024; the GPT Store and Custom GPTs cover the same territory via built-in actions and secure knowledge files. Ready-made GPTs for design, travel, or automation live under Explore GPTs, while a no-code wizard lets you craft your own.

Popular Custom GPT categories:

Writing assistants
Code reviewers
Language translators
Research helpers

4. Try Advanced Voice & Vision

GPT-4o delivers near-real-time voice and image understanding, adding nine expressive voices and two-way translation. On mobile you can share camera or screen during voice chats; desktop sports the same mic icon. Free users get a daily GPT-4o-mini quota.

Voice features to explore:

Real-time conversation
Language translation
Image description and analysis
Screen sharing capabilities

5. Pick the Right Model

GPT-4 was retired inside ChatGPT on 30 April 2025 and fully replaced by GPT-4o and lighter o1-mini/4o-mini variants. GPT-4o is natively multimodal, so select it for tasks that involve images, audio, or nuanced reasoning.

Model selection guide:

GPT-4o: Best for complex reasoning, multimodal tasks
GPT-4o-mini: Faster responses, simpler tasks
o1-preview: Advanced reasoning for complex problems

6. Control Output Format, Tone & Emotion

GPT-4o follows granular style cues: tables, JSON, Shakespearean sonnets, or subtle emotional tones. Pair concise Instructions ("Default to GitHub-flavoured Markdown; avoid fluff") with inline prompts ("Return budget as CSV") for precise results.

Format examples:

"Respond in bullet points"
"Use a table format"
"Provide JSON output"
"Write in a casual, conversational tone"

7. Work in Projects & Use Connectors

Projects wrap persistent tasks with file uploads, citations, and memory; the file limit doubled to 40 for Pro users in June 2025. Connectors (Google Drive, Dropbox, GitHub, SharePoint) pull trusted data directly into a Project for research or coding pipelines.

Project benefits:

Persistent context across sessions
File upload and analysis
Citation tracking
Team collaboration features

8. Lock Down Privacy & Data Use

The revamped Data Controls panel splits three toggles:

Chat History & Training — opt-out of model training on new chats
Memory — disable both saved and implicit memories
Export Data — download a ZIP before purging

Settings sync across devices, and Enterprise/Team accounts exclude chat data from training by default.

Privacy recommendations:

Review data controls monthly
Use Temporary Chat for sensitive topics
Export your data regularly
Understand your plan's privacy features

9. Theme & Layout Tweaks

Switch between Light, Dark, and Compact under Settings → Theme. Heavy customisers inject their own CSS with browser style-plugins to change widths, fonts, or colours, but remember these tweaks live only on your machine and may break after UI updates.

Customization options:

Built-in themes (Light, Dark, Compact)
Browser extensions for advanced styling
Custom CSS injection
Layout modifications

10. Shortcuts & Automations

Press Ctrl+/ (Cmd+/) to view all shortcuts. New entries include Ctrl+Shift+S to toggle the sidebar and Alt+Space (Windows) to open ChatGPT anywhere. On iOS 18, map a Voice-Chat shortcut to the Action Button; macOS and Windows desktop apps also support global hotkeys.

Essential shortcuts:

Ctrl+/ - View all shortcuts
Ctrl+Shift+S - Toggle sidebar
Alt+Space - Open ChatGPT (Windows)
Cmd+K - Quick commands (Mac)

Final Thoughts

2025 is the year of personalisation everywhere: ChatGPT now learns across sessions, remembers inside Projects, and adapts tone on the fly—while giving you clearer switches to erase or mute that knowledge whenever you like.

Combine Memory, Custom Instructions, and Custom GPTs, then layer on Projects, Voice, and Connectors, and you'll have an assistant that not only speaks your language but also understands your workflows.

Getting started checklist:

Set up your Memory preferences
Write effective Custom Instructions
Explore the GPT Store
Try Advanced Voice mode
Configure your privacy settings
Learn the essential keyboard shortcuts

Start with these fundamentals, then gradually explore the advanced features as your needs evolve. The key is finding the right balance between automation and control that works for your specific use case.