Knowing what customers actually do.
WHAT TO SET UP
Web analytics on the whole site Ecommerce tracking, so you see revenue and which products sell
The checkout funnel: product view, add to cart, checkout begun, order placed
WHAT THE FUNNEL TELLS YOU
Where customers leave. If most drop between add to cart and checkout, delivery cost or the account requirement is likely the cause. If they leave at payment, the gateway or the trust signals need attention.
This is the single most useful thing analytics gives a shop.
WHAT ELSE TO WATCH
Which products get viewed but not bought, which usually means the description or the price Where traffic comes from, so you know what is working Mobile versus desktop conversion, which on a Nigerian shop should be mobile-heavy
PRACTICAL POINTS
Exclude your own visits, or your figures are meaningless on a small shop Do not check daily. Small numbers are noise Analytics scripts add weight. Add what you use and remove what you do not
PRIVACY
Analytics collects personal data. Say so in your privacy notice.