Playbook: Optimize your above-the-fold slot

Playbook: Optimize your above-the-fold slot
What it does: your highest-RPM unit — squeeze it before touching anything below.

Setup (effort 2/5):
— Never lazy-load the ATF leaderboard/box. It should request on page load, immediately.
— Reserve its exact height in CSS so it never causes the page's largest layout shift.
— Make it your highest floor — ATF inventory commands premium CPMs, price it accordingly.
— Don't refresh it on a timer tied to scroll; refresh on dwell instead, since readers linger at top.
— A/B 300x250 vs 336x280 vs responsive — the extra 36px width often lifts CPM measurably.

RPM lift seen: +5-10%, because ATF is a disproportionate share of total revenue.

Pros: biggest single lever on the page. Cons: also the biggest LCP/CLS risk if mishandled.

Lift: ★★★★☆ — Risk: ★★☆☆☆
Best for: every site. The one slot worth obsessing over. Skip nothing here.