I’ve been an Amazon seller for almost 4 years, and for the longest time I was stuck obsessing over ACOS, tweaking bids every day, and chasing every new ad hack I found online. Nothing felt stable, and I couldn’t figure out why my ads worked for a week then crashed.

Then I started breaking down Amazon advertising using First Principles—stripping away all the noise, assumptions, and surface-level tricks to focus only on the basic, unchanging facts of how ads really work. It completely changed how I build and optimize campaigns, and I want to share exactly what I learned, in case you’re stuck in the same cycle I was.

First Principles just means starting with the most fundamental truths, not someone else’s “best practice” or random case study. You dig down to the root of how something works, and build your strategy from there. Tools like the 5 Whys or fishbone diagrams help, but you don’t need anything fancy—just clear, logical thinking.

What Amazon Ads Actually Are (The Core Truth)

At the most basic level, Amazon Ads = a traffic distribution system.

They’re not a magic button for sales. They’re just a tool to get your product in front of shoppers.

The real, non-negotiable purposes of ads are:

• Get more impressions to drive sales

• Boost organic rankings by increasing search velocity and conversions

• Test keywords and product-market fit quickly (MVP validation)

• Retarget shoppers to improve repeat purchases

• Clear inventory or compete fairly with similar listings

Ads are never meant to burn budget for useless data, or chase endless low-quality traffic.

The Core Components That Make Ads Run

Every campaign works off the same building blocks:

• Keywords / ASINs: What triggers your ad to show

• Bids: How you compete for visibility

• Ad placements: Where your ad appears

• Audiences: Who sees your ad

• Conversion actions: Clicks, add-to-carts, purchases

• Algorithm feedback: CTR, CVR, ACOS, ROAS from the COSMO system

How Amazon Really Assigns Impressions

Your ad visibility follows a simple, unchanging formula:

Impressions = Relevance × Bid Strength × Listing Quality

Every time a shopper searches, the system does three things:

1. Checks if your targeting matches the search intent

2. Scores your bid + listing quality

3. Assigns your ad to a placement

That’s why optimization always comes down to three things:

• Tighter, more relevant targeting

• Bids that fit your actual goals

• Better listing content (main image, title, reviews, price) to lift CTR and CVR

The Only Ad Metric That Matters Long-Term

Nearly every seller fixates on short-term ACOS, but First Principles tells us to look at net positive value.

Your ads are working if:

• Total gross profit from ads + organic lift > ad spend

• Ads push your organic rankings higher

• Your product lifecycle speeds up (faster launches, steadier sales)

I saw this clearly with a home goods product I launched. I pushed bids for top-of-page placements to rank faster, and my ACOS was very high at first. But orders climbed, core keywords moved onto page 1 organically, and I qualified for a BD. After running the BD, organic orders took over, and the listing turned consistently profitable. Short-term ad spend turned into long-term organic growth.

SP / SB / SD: The Simple, Real Differences

You don’t need complicated explanations—here’s what each one actually does:

• SP: Captures search intent, drives direct orders

• SB: Builds brand awareness, locks in top-of-search placement

• SD: Retargets shoppers based on browsing and behavior

The #1 Rule Before Launching Any Ad Group

Before you turn on any campaign, be able to answer these four questions clearly:

1. What is the exact goal of this group?

2. Who am I targeting?

3. What targeting method am I using?

4. How will I measure success?

For new launches, you have two reliable paths:

• If you don’t know the market: Start with auto ads to test keywords and listing strength

• If you know your keywords: Launch structured manual groups (core exact, broad/phrase expansion, competitor ASIN targeting)

How to Diagnose Any Ad Problem

All performance issues fit one formula:

Results = Impressions × CTR × CVR × AOV

• Low impressions: Targeting too narrow, bids too low, competition too high

• High impressions, low CTR: Main image weak, title/reviews/price uncompetitive, bad placement

• Clicks but no conversions: Traffic not relevant, listing unconvincing, poor value

• Conversions but high ACOS: High CPC, low AOV, redundant targeting

Multi-Variant Listings (Like Apparel) – The Biggest Mistakes

If you sell clothing or multi-variant products, you’ve probably felt the pain of unstable ads. Here’s what’s really happening:

1. Amazon naturally pushes traffic to top-performing child ASINs

2. Mixing too many variants in one group drags down high performers

3. SP ads bid at the ASIN level, not parent or color level

4. Too many low-data variants make optimization impossible

The fix: Winner retention method

Keep only top-performing ASINs and campaigns. Pause the rest. Test new, clean groups slowly.

Internal Competition: The Silent Killer of Ad Performance

If you run the same keywords across multiple campaigns—even different match types—you’re competing against yourself. Amazon can’t prioritize, so all your campaigns get weaker.

Rule of thumb:

• Same keyword, different match types: SAFE in one campaign

• Same keyword across multiple campaigns: RISK OF INTERNAL COMPETITION

Fix: Use exact negative keywords to block overlap between campaigns.

One Small Habit That Saved Me Thousands

Track your stable conversion placement and CPC over time.

Most ad drops aren’t from your listing—they’re from CPC inflation or lost ad positions. Adjust bids to hold your best converting spots, and you’ll stay consistent.

For apparel and similar categories with long consideration times, don’t fixate on instant conversions. Impressions are often more important early on.

Final Thought

Ads are just a tool. They won’t fix a bad product or a weak listing, but when you build your strategy on fundamentals instead of hacks, they become reliable, scalable, and far less stressful.

Every category is different, so test small and stay consistent.

What’s the biggest ad problem you’re fighting right now? High ACOS? Internal competition? Multi-variant chaos? Drop a comment—I’ve probably dealt with it too.