"Make it modern and clean, similar to these three sites we like" is the most common website brief in existence, and it's also one of the least useful. It gives a designer almost nothing to actually work with beyond aesthetic preference, which means the result depends entirely on the designer's own judgement filling in every gap the brief left open, for better or worse.
Start with what the site actually needs to do
Not "look professional", which is a description of a feeling rather than an outcome, but a specific primary action: get a form filled in, get a call booked, get a product added to a cart. Every design decision, from the homepage layout down to a single button's colour, should trace back to making that specific action easier, not harder. A brief without a clear primary goal produces a site optimised for nothing in particular.
Describe the actual visitor, not an assumed one
Who genuinely lands on this site, and what do they already know when they arrive? This single question, answered honestly rather than aspirationally, tends to reshape more of a brief than any other single input. Someone arriving from a Google search with a specific problem needs a different homepage experience than someone arriving from a personal referral who already trusts the business. Being specific here, even a rough sketch of two or three real visitor types, gives far more useful direction than a generic "our target audience is businesses like ours."
Bring three real examples, not vague adjectives
"Modern and clean" means something different to every single person reading it. Three actual reference sites, with a specific note on what's genuinely liked about each one, homepage layout, navigation style, tone of the copy, gives a designer something concrete to work from instead of a personal interpretation of a subjective word.
Be explicit about what has to stay from the old site
Existing URLs that rank well and shouldn't change without a proper migration plan. Content that's performing and shouldn't get rewritten just because everything else is being redesigned. Brand elements that are non-negotiable versus ones that are genuinely open to change. Without this, valuable existing assets sometimes get discarded simply because nobody explicitly said to keep them.
Set a realistic budget range upfront
Vague budgets produce vague proposals, since an agency scoping blind has to guess at a range and often defaults to guessing high to avoid underselling. A stated range, even an approximate one, lets a proposal actually match what's realistic rather than everyone working from different, unstated assumptions about scope.
The brief is a starting point, not a contract
A good brief doesn't need to answer every question perfectly, it needs to give a designer or agency enough real information to ask better follow-up questions. Treating it as a living document that gets refined through the first few conversations, rather than a one-time document that has to be perfect before anyone touches it, produces a better working relationship and, usually, a better result at the end.