The summary.
ONE TYPEFACE IS USUALLY ENOUGH
Vary size and weight within one family. Check that capital I, lowercase l and the digit one are distinguishable — that confusion causes real errors in references.
DEFINE SCALES AND USE THEM
A handful of type sizes, a small spacing scale, a limited palette.
Arbitrary values produce subtle inconsistency that reads as carelessness. Audit what you actually use — it is always more than intended.
TEXT SIZED ON A DESIGNER'S SCREEN IS TOO SMALL IN USE
Test by reading a full paragraph on a phone, outdoors.
CONTRAST FAILS MOST OFTEN WITH GREY TEXT CHOSEN BECAUSE IT LOOKS REFINED
And with text over photographs. A phone in direct sunlight loses all subtle contrast, which here is a normal condition rather than an edge case.
NEVER LET COLOUR CARRY MEANING ALONE
Pair it with text, shape or position. Test in greyscale.
ICONS RARELY EXPLAIN THEMSELVES
Very few are universally understood. Pair them with labels, and test by showing one alone and asking what it does.
USE YOUR OWN PHOTOGRAPHS
Visitors recognise stock imagery immediately, and it reduces trust.
WHEN BRAND AND LEGIBILITY CONFLICT
Keep the brand colour for identity and use an accessible variant for text. Illegible text does not serve the brand either.
