Not just what you want to hear...
Beta readers are useless unless you take their comments seriously. Speaking of which, the number 1 thing my beta readers pointed out to me was:
THE CURSE OF KNOWLEDGE
Meaning that the writer knows what things are, how they work, who people are, etc. You can't assume your readers know all this stuff, or that they'll pick up on subtle cues you write into your story.
Occasionally, my readers have been amused that I bothered to describe what a bat'leth looks like, what a mek'leth is, how a dk'tagh works. I did that because some of my readers have a vague idea of what a klingon is, but no clue what those weapons are or how they work.
Also, I invent lots of devices and found I had to explain those as well. For instance, the Cardassian band rifle, which works a lot like a Tommy gun. Even though I described it in use, I found I really needed to introduce it as a "repeating projectile weapon, not unlike a machine gun." (Why would cardassians have something like that? Because it works inside an energy dampening field, when phasers don't...)
This brings to mind a potential pitfall in my own writing. I don't think I spend much time describing well-known species like Vulcans because I'm taking it on faith that readers of Trek fanfic know what Vulcans and other well-known species look like. I perhaps spend even less time describing well-known starship classes.