One thing every writer should do is read outside what they write, if you write hard science fiction you should read more then hard science fiction published recently.

This is important first to give you a deeper bag of tricks, similar to how knowing history is important. You don’t want to just repeat what all your direct competition is doing after all.

I have always loved mythology, one thing I find fascinating is how different the themes are. The theme of the Odyssey is humility before the gods. That is not a theme your likely to find in modern books in the west. Nor for example would a book where the message is that you should trust the government.

All of that said, you do need to keep in mind you are trying to sell a product. You don’t want to model your book after one published fifty years ago, even one that was a best seller.

I love the Lensmen books, but I would never try and sell books that short today.