The logo appears once. The body text appears on every page, every product, every line of the checkout. At sixteen pixels on a phone, in a hurry, it is the only part of your brand most customers ever read closely. Treat it that way.
Choose one typeface and learn it
A second typeface is a second opinion. Most stores need one: a sans with a real range of weights, drawn for screens, with numerals you can read at a glance. Use a display face, if you must have one, for headlines only, and only above forty pixels. Everywhere else, the workhorse.
Your brand is the body text, not the logo.
Two sizes, two weights
Body and heading. Regular and medium. That is enough hierarchy for a product page, a collection and a cart, and it is far easier to keep consistent than a scale with seven steps. When everything is emphasised, nothing is.
Set the line length and leave it alone
Sixty to seventy characters on desktop; whatever the phone gives you. A description that runs the full width of a large screen is not easier to read because it is bigger. It is harder, because the eye loses the line.
Make the price the clearest thing on the page
Look at a product page from arm's length. The price should be legible before anything except the product name. If it is not, the type is doing decoration instead of work, and no colour or photography will make up for it.
Check the numerals
Prices, quantities, sizes, dates. Tabular figures line up in a cart; proportional ones wander. Look at a 1, a 7 and the pound sign together. If they are ambiguous at sixteen pixels, the typeface is wrong for a shop, however good it looks in the logo.
Set the body text well and the store looks designed before a single photograph loads.
