The best steps you can do for your business are have a very firm commercial idea of what success looks like (i.e. measure LTV, churn etc by channel) and have a robust framework for market research. I personally like the idea of splitting spending marketing spend between branding (where your aim is to promote unprompted brand awareness) and acquisition (where you want CPA < LTV.) Also remember there are A LOT of businesses which spend money in things that an expert can identify as not commercially sound - so audits by external agencys can be useful (i.e. not using negative keywords in AdWords and spending many thousands on direct response campaigns that don't work.)
I'll add the cavaet that rhe worst thing about "attribution" I've found is it puts an unfair amount of pressure in the bottom of the funnel. Brand focused marketers aren't really held to scrutiny at all (lots of marketing teams in businesses I know don't even do total spend / total sales) - I think this can cause some resentment between teams.
Good articles on this are few and far between but this one I don't mind https://www.cmo.com.au/article/641243/iag-marketers-must-end... as well as Willem's talk on what they did to bring programmatic in-house at Foxtel.
Happy to connect with anyone interested in this space.