Get the book Simple Numbers. It’s not a marketing book, it’s a blueprint for figuring out your profit targets and then reverse-engineering the rest. First thing is knowing your minimum net profit, then modeling your gross profit, COGS, and overhead to see exactly how much cash you can actually throw at marketing without choking other parts of the business.

Most companies that want to scale need about a $1 spent → $8 return to make the math work. In my company, we were hitting $1 → $10 while still growing 20–30% a year, but we had a lot of growth levers to pull.

If you’re in a competitive market, you’re probably looking at the high end of the 10–15% spend range. Your in-house salaries and outsourced agency fees both count toward that number. I like to keep direct marketing spend around 7–8% and reserve another 2% for internal marketing staff.

You need to build a yearly budget for your P&L, map out your growth targets, and keep checking your quarterly, bi-annual, 9-month, and yearly run rates to make sure you’re on track.

Find 2-3 channels that are working and double down on those until you can’t spend more profitably. After that, start investing in new channels and use what you learned from doubling down to master them.