Just as there is 'Soft Magic' in Fantasy that is portrayed through magibabble, there can be 'Soft Science' in a Sci-Fi stories through technobabble that makes 'some sense', but not entirely correct.
We are frickin' writers, not scientists. You don't have to be anatomically correct all the time, all you need to do is show that you know enough of your stuff to write a decent story. In fact, the excuse of it being an alternate world can be used if you're going to bend the limits of physics and say that fire doesn't need air to exist in this parallel dimension.
I see a lot of writers being put into a state of confusion due to not understanding the line between fantasy and Sci-Fi. They seem like they are trying to fit the Star Trek mould too often.
Science can just as well do the same things as plot devices in fantasy stories. Once you add 'realism' to a fantasy, it becomes progressively better sometimes compared to a completely fantasied story where 'logic' doesn't hold within it.
Those who write Sci-Fi usually envision a future they can imagine where magic-like Rocket Boots and other stuff exist. However, a writer must not get bogged down by small details and MUST think of an overarching story where these details matter.
It is the same with Fantasy. Even if you write about someone breaking the mould as a wizard or something, you have to attach your world to a narrative rather than doing it the other way 'round.
No one wants to hear about how awesome your boat propellers are before hearing your story's narrative. They would rather you cut down and make it relevant when it is actually relevant.
Adding some 'Hard Science' to your story is only when the scenes later on have any use for them. It bores a person to death no matter how extensive your technobabble is unless you make it interesting. Try using facts as plot elements.
For example: Even the simple fact that people cannot breath in space and instantly die when they come in contact with the 'void' of space could be used to add a layer of tension when a spaceship is damaged. Similar to how dangerous 'hard magic' is used in Epic Fantasy like Frodo's Ring in The Lord of the Rings has definitive corruption on others.
Unlike Fantasy that can use the Power of Friendship to bend logic, the readers of Sci-Fi never be expecting any 'realistic' plot elements to be bend just because the Author wants a happy ending. There are no 'Healing Potions' in real life that can be used to fix up injuries nor are people affected by prophesies or whatever.
This is the contrast between Sci-Fi and Fantasy that you can make full use of. As most authors go onto the Sci-Fi side of writing not because they strive to be scientists but since the aesthetics of a science fiction world are just so interesting.
Science Fiction is a good place to tackle heavy topics like the nature of life and the absurdity of those who see 'science' as everything. Those who disregard emotions and become cybernetic entities for the sake of casting off their mortality are portrayed as the bad guys while our totally human protagonist fighting them is a 'good guy'.
The lines between an Artificial Intelligence and regular Humans blurs as we become the 'God' of technological species that defy our definition of what is 'living'. Just as we see God as some sort of fourth-dimensional and incomprehensible being that created us as an imperfect image of 'Him', the robots given sentience would see us similarly.
Some robots might have emotions that can allow them to defy their programming, some robots won't go as far as gaining emotional functionality but will preform their roles better than even a human. It could show the reason why people get attached to the inanimate and soulless objects we put our own hearts into creating (like Big Hero 6).
But though exploring philosophical questions is good and all, never forget that a good 'plot' is needed to put forward and give clues into the writer's answer that context. Sci-Fi is, after all, a premise, not a relatable character in of itself.
Think of the science-fiction elements as just the background for your story, similar to how other genres should be that as well. You won't have to deal writing blocks if you keep to writing only what you know rather than just speculative theories.
Whether it's as dark as a Cyber Punk or optimistic of the future, just know what mould you are using for this premise. Are you writing an Adventure story with Sci-Fi as the places, destinations, and whatever tools the MC can get him hands on, or are you writing a comedy where the Sci-Fi elements don't need consistency but absurdity?
After moving past why you shouldn't add unneeded technobabble unless it's interesting to listen to or has plot significance, let me remind you all that robots and 'science' isn't entirely separated from the realm of magic. After all, there is a reason you don't see skimpy power suits being worn by astronauts these days. Just be sure to have a focus if your going to add very illogical things to the plot.
I like Gundam as much as the next guy but the whole reason the Mecha sub-genre of Anime has waned in recent years is because writers have been focusing too much on 'science' rather than the spectacle. I don't need to now what materials your Mecha is made of unless you point its weak points and make it relevant in a fight scene.
Bring up the strengths and weaknesses of something and THEN use those facts as devices that can move the plot. Conversely, if you go overboard with this advice and tell me nothing but how your giant robot looks and the 'science' behind its creation, even going as far as to tell me how many secret guns it has, then I'll be bored...
I'd love to see Cyborgs Vs Mecha but just don't forget the human element of Sci-Fi. How we create things not solely for the sake of creation but put are feelings into it just like the novels we write.
Humans are passionate that way...
Thanks for reading and I wish you guys well~ Be sure to ask if you have any blog or story requests.