Jump straight to a specific problem.
Going back to sleep isn't always the right call — it depends how long you've got left. That one glance at the clock to check is the exception to the "don't clock-watch" rule — it's the repeated checking afterwards that causes problems, not this single check. Tell us how early you woke and we'll suggest what to do.
Picture a random, neutral word, then let your mind drift to another completely unconnected one, then another — e.g. "kettle... orange... bicycle..." — without linking them into a story. This is sometimes called the "cognitive shuffle" in sleep research; it's an established technique, not something we invented for this guide.
Pick a category — animals, foods, cities — and go through the alphabet naming one for each letter you can. It's concrete enough to hold your attention without being emotionally engaging.
Pick an unfamiliar number — 13, 17, 19 — and work through its times table. The unfamiliarity is what makes it effective: familiar ones (2s, 5s, 10s) are too automatic to hold your attention.
Mentally walk through somewhere you know well but don't feel strongly about — your regular supermarket, a route you often walk, or a hotel you've stayed in more than once — picturing the layout and small details as you go. It's absorbing enough to occupy your attention, but has no emotional stakes to keep you alert.