Step 13: Write one simple sentence that explains your idea

Okay, the fit is tested, boundaries are set, and the fluff is stripped. Time to make the call.

This is a test: does the idea make sense in plain language? If you cannot describe your idea clearly in one sentence, it's likely that you're still holding too much complexity in your head. Psychologists call this the curse of complexity - when you try to hold too many ideas at once, none of them land clearly. Research shows that people can only hold about 3-4 chunks of information in working memory at a time. If your description requires more mental juggling than that, you've lost them before you've finished speaking.

You're not trying to be persuasive or clever. You're trying to be accurate. The sentence you write should describe what the idea is, who it helps, and what it helps them do. Nothing more, nothing less.

Clarity beats cleverness every time. The best descriptions feel almost boring in their simplicity. That's not a bug - it's a feature.

What To Do

Elevator test: One sentence that states what it is, who it helps, and what it helps them do—nothing more, nothing less.
  • Be accurate, not clever.
  • Use everyday words.
  • Keep it to a single clean sentence.

Try this framework: "We help [who] to [outcome] by [how]."

You don't need to get it perfect. You're aiming for something clear enough to be useful—a baseline description you can test against reality. You can improve or refine it later, but this becomes your reference point for everything that follows.

Think of this as your elevator test: if someone asked you what you're building while you're walking to your car, could you give them a straight answer that makes sense? If the answer involves three sub-clauses and a bunch of explaining, you're not there yet.

What's next

Right. Clear, simple sentence in hand. But what if, after all this work, you *still* feel uncertain? What do you do when you genuinely don't know the answer?

This isn't your final marketing tagline or elevator pitch. It's your clarity check. You're testing whether you can explain what you're building without confusion, jargon, or multiple attempts. If you can't do this clearly, everything else becomes harder.

Cognitive load theory, developed by psychologist John Sweller, explains why complex descriptions fail: when you overload someone's working memory, they can't process or retain what you're saying. Working memory can typically hold 3-4 "chunks" of information at once. If your idea requires more than that to understand, it won't stick - not because people aren't smart enough, but because you're asking their brain to do too much work.

This is why one-sentence descriptions are so powerful. They force you to compress your idea into something that fits easily in working memory. If you can't do that, you're either still unclear on what you're building, or you're trying to build too many things at once.

Example: Compare these two descriptions:

"We're a multi-platform wellness ecosystem that synergises evidence-based nutritional guidance with personalised fitness protocols and mental health resources to optimise holistic wellbeing outcomes."

vs.

"We help busy parents eat better without spending hours meal planning."

The first one requires you to hold 6-7 concepts in your head simultaneously (platform, wellness, ecosystem, nutrition, fitness, mental health, optimisation). The second one has 3 chunks (busy parents, eat better, no meal planning). The second one lands. The first one doesn't.
Practical takeaway: If your one-sentence description requires someone to pause and mentally unpack it, you've exceeded cognitive load. Test this: say your sentence out loud to someone who knows nothing about your business. If they need to ask clarifying questions immediately, simplify until they nod and say "Got it."

Plain English: Your brain can only hold about 3-4 ideas at once. If your description throws more at someone than that, it bounces off. One clear sentence isn't just good practice - it's respecting how human memory actually works.

The Spark: Ella Mills, founder of the plant-based brand Deliciously Ella, started with a blog and ended up with a food empire. But success came with costs she didn't anticipate.

In interviews, she's spoken openly about what scaling demanded: working seven days a week, shelving friendships, delaying having children, stepping away from her original content. Her brand grew, but the version of herself she built it around had to be left behind.

The Real Lesson: Success stories often hide the swaps. You don't see what was traded away - only what scaled. Ella's success came with massive time, energy, and identity costs. She built something impressive, but had to rebuild herself later.

Your one sentence isn't just about what you're building - it's about who you'll need to become to build it. Make sure you're willing to make that trade.

Finding purpose and putting mental health first - Ella Mills Interview

Use these AI Buddy prompts to get clear, direct support as you work on your one-sentence description.

  • "I'm trying to explain my idea in one sentence but it either sounds too vague or too complicated. Can you help me find the clearest way to say what this actually is and who it helps?"
  • "I've written my one-sentence description but I'm not sure if it captures what I really want to build. Can you help me spot what might be missing or unclear?"

You can keep refining this line as you build, but start with what feels clear and true now.

If you can't explain your business idea while walking to your car, you're not ready to build it. Clarity isn't the last step - it's the foundation everything else stands on.

When you read your sentence back, does it describe something you'd actually want to use yourself? If not, what's missing?