The most recent novel Eunice and I published is a post-cyberpunk novel set in LA in 2053. We did everything in our power to extrapolate from existing trends and technologies, but hunestly, some of the details were outside our knowledge.
So we asked for help.
A lot of folks contributed to that particular novel. We talked to experts in everything from imaging technology to contact-lens-mounted displays to linguistics to medicine, and even sent chapters from the first draft to people whose domain knowledge exceeded ours.
Bill Otto consulted with us on IR and Doppler imaging. We talked to Jamaika Campos, who has a doctorate in linguistics and did her Ph.D. on exactly the type of subcommunity that appears in the book, about the language and culture of T-Town. Jon Lowry has actually done work on building prototypes of thin-film contact-lens displays, and generously contributed his time and knowledge. Ileen Verble offered us the benefit of her experience with trauma medicine for a crucial scene.
In a sense, most of science fiction is never going to be “write what you know,” especially hard SF. You can write what is plausible, you can seek to extend from the here and now by extrapolating from what’s happening, but you’re always going to get it wrong. What we set out to do is to write what might happen, not what will happen, if that makes sense.