Start with Simplicity
There's no need to go overboard. If you have an idea start with the smallest possible implementation of that idea. Strip away all the cruft, the distractions, the little nice things. Tear away as much as you can while still being able to recognize the thing that makes your idea special.
Keeping things simple is beneficial in several ways. By focusing on one small single thing you won't get distracted with unneeded features. The smaller your idea the faster you'll be able to implement it, which means the faster you'll start getting real world feedback.
Focus on one small idea. Keeping your idea small means that you'll spend most of your thinking on that one small idea. More thoughts mean more refinement. You'll have a deeper understanding of the problem space resulting in an implementation that has been through hell in back even if just in your imagination.
Keeping your idea simple means you will be able to make it faster than if you had a huge grand idea. The pace of the world today demands speed to even compete. By focusing on the smallest part of your idea that works and building it fast and getting people actually using it.