Test Proof of Principle
The key question here is - what is the most important, yet unproven part of your idea? These resources will support you to apply scientific best practices to validate the technical hypothesis underlying your project. Remember, you're searching for the truth, not trying to be right.
Validate the fundamentals
Y Combinator have written this great blog post about 'The Scientific Method for Startups'. It emphasis the importance of staying true to this approach, even for commercial projects.
Apply the Scientific Method
Define your hypothesis
This will be based on a technical assumption that would need to be correct in order for your solution to work.
Design an experiment to test your hypothesis
The experiment should provide quantifiable, verifiable, replicable, defensible support that your hypothesis is true.
Work out what resources you need
Work out what resources you will need to perform this 'proof of concept' experiment (including time, access to facilities, equipment and expense).