The first thing is a clear steer on what you want the page or site to achieve, and any ideas you’ve already had about what you do or don’t want it to look and behave like. Sometimes examples of websites you absolutely hate are as useful as those you love. If you’ve already got a website that is being replaced, a list of pain points and positive qualities is very helpful.
On a practical level we’ll need a copy of your logo and any branding guidelines, photos, graphics and text you already know needs to be worked in. If you’re unsure of exact content we’ll use placeholders at this stage, but real material is preferable where possible.
The last thing we need is honest and prompt feedback. You’ll be sent a static image of what your site is going to look like, either as a JPG or XD document, but this is only a starting point – we’ll take your comments and rework it until you’re 100% happy with the end result. Only at this point will we begin to code the flat design into a working website.