Does anyone know what places I should look for good tech writers? Or any recommendations
I think a good approach is to hire junior developers/interns and just ask them to build stuff off your API from scratch and carefully record their pain points, questions, etc. As a bonus, the stuff they build can also later be used as working "best practice" examples -- assuming you get your developers to code review them.
I say junior developers because they're a good knowledge baseline to aim for and are probably not "contaminated" with a priori knowledge of your system or similar alternatives.
- making it easy to find what I want (good search, helpful table of contents, etc.)
- lots of examples for every method signature or REST call
- complete use-case writeups with runnable examples
If you noticed I said examples multiple times, then I think I've made the point I intended to make.