The best design thinking tool is asking questions, acquiring information and learning new things.
Onur Cobanli explains:
If you wish to have a long term business, you need to have good design. Good design is about creating meaningful and valuable products that people desire know and preferably also tomorrow. You want to sell good design so that you can have repeat customers and so that you can profit not only in the short term but also in the long term, but remember good design is dynamic, it should adopt to future challenges.