You can still stand on the shoulders of others when you are a solo developer. That might sound obvious, but you can offload an enormous amount of brain-power to the work of others due to the neural nature of the net. I consider the net my 'exobrain' and it's worth learning how to get answers rapidly using multiple different search engines. Google is handy, but it's worth investigating the native search capabilities of other sites.
One obvious search mechanism is, of course, Stack Overflow. HN's Algolia search is another. Personally I run Searx[1] locally and permanently have it open when coding.