Great work mate, being a marketer and having worked with startup and ecommerce businesses, I can offer some piece of advice. 90% chance of failure can be reduced by this.
Things Not to do.....
1. I have worked with startups where owners don't know much about business (They don't need degree though), For Example, all they want is quick profit and see good ROAS in ads dashboards (Google ads, Social Media Ads). My friend, this is not success, infact it is failure in many accounts I audit. Your Success Metrics are MER, CAC, nCAC and LTV. Whoever, you hire for Advertising, ask them about these (I bet the majority don't know about it). If they can improve it, work with them, otherwise don't rely on what's showing inside the Ads platform.
2. Your competitors are one click away. From your traffic (be it influencers or others) make sure your offer is better, These things still work, "You give more value, I will buy from you"
3. In e-commerce marketing, you will profit only if the customer buys from you 2nd time. Read it Again
I hope you understand these things, if not you can read this and emphasize on these metrics. I wish you the very best of luck