I’d spent hours building visualisations for my application to The Data School - wrestling messy Excel files, watching hours of YouTube tutorials and figuring things out through trial and error on Tableau. Within just a few days here, I realised how much I’d been winging it. What I hadn’t appreciated before is just how important planning and preparation are.
We didn’t start the first week by jumping into Tableau. Instead, we stepped back and looked at the bigger picture: what makes “good” data, what can go wrong, and why structure matters so much when preparing for analysis.
We covered granularity, common data issues, and the difference between just owning data and having it in a format you can actually use. We learnt that clean, structured data saves hours later on - making everything much smoother when creating visualisations.
Our first Tableau Prep project at the end of week 1 brought it all together. Starting with a messy dataset and shaping it ourselves made the importance of preparation feel very real. Presenting our plan to prepare the data back to the group showed just how much easier things become when you build on solid foundations.
Key Lessons I’m Taking Forward:
- Plan before you build.
Having a clear approach makes a huge difference. Using excalidraw has really helped me visualise what I am trying to do, whether this is for preparing data, or building vizzes.
- Clean data saves time.
Tools like Tableau Prep are key to getting everything into shape early, so you’re not constantly fixing issues later on.
- Preparation beats improvisation.
Starting with a plan gives you direction and saves you from having to undo work down the line. A few extra minutes of prep up front can save hours later.