Honestly, it's a bit of a balancing act. You want to stay faithful to the original episodes while trying not to highlight the fact that, basically, you're writing a period piece set during a 1960s vision of the future.
I will say most of you guys do a good job with that, even offering explanations from time to time why something that may have appeared more primitive on screen really is not, in universe. It takes a little imagination but for the most part I think it works. When I'm reading an original series novels these days I try to envision things as presented by the remastered episodes, with the improved special effects and planetary settings. I find that helps keep it futuristic for me.