Updates fix security problems, so they matter. Take a backup before you update, update a few plugins at a time, and check the site after each batch.
Every plugin you delete is one fewer thing to keep up to date. Deactivated plugins still sit on the server, so delete the ones you no longer need.
An About page is often the second page a new visitor opens. They want to know who you are, what you do and why they should trust you.
Open with the problem you solve and who you solve it for. The history of the business can come later, and briefly.
A few minutes of checking saves an embarrassing correction later. Run through this list before any new page goes live.
Large photos are the most common reason a page feels slow. Resize images to the width they are shown at, and use a modern format where you can.
Always add alt text that describes what the image shows, for visitors who cannot see it.
When something goes wrong, a calm, practised restore gets the site back quickly. Work through these steps in order.
Keep a note of when the backup was taken, so you know which changes need to be made again afterwards.
A backup is only useful if it is recent enough to restore from without losing work you care about. The right backup schedule depends on how often the site changes.
A brochure site that changes once a month is well served by a weekly backup. A shop or a busy blog that takes orders or comments every day needs a daily backup at the very least.
A backup you have never restored is a hope, not a plan. Restore a copy to a test site every few months and check that it works.