Jakob Nielsen's 10 general principles for interaction design. They are called "heuristics" because they are broad rules of thumb and not specific usability guidelines.
Proof of concept in software development is a controversial topic. The person that came up with a software idea is usually convinced of its relevance. And stakeholders usually don't want to spend time on something that is not even going to be included in the final product.
Startups, Biz Dev
Proof of Concept in Software Development
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100 Tools to Launch & Grow Your Start-up Without Web Weveloper, Graphic Designer and (almost) Without Money
Anyone including non-designers can use this framework to analyse a product or service or analyse a piece of work for a potential client. You could even use this to review your own work as the tools and techniques I use leave little room for bias.