Most underperforming accounts I take on, whether they're lead gen or ecommerce, don't have a creative problem or a bidding problem. They have a measurement problem. The platform is optimising towards the wrong signal, the conversion data is incomplete, and every decision after that is based on figures that aren't accurate.
So I fix the tracking first. Server-side tagging, Enhanced Conversions, offline imports for lead-gen, purchase and value tracking for ecommerce, a data layer that fires reliably. Once the bidding is being trained on accurate, complete data, it starts pulling its weight. Only then is it worth scaling spend.
The other half of the job is commercial. A strong CPA means very little if the leads don't close, and a strong ROAS means very little if AOV is propped up by discounting or the customer never comes back. I focus on the numbers that matter to the business, not just the ones reported in the ad platform. That's the difference between managing budget and actually driving growth.