I often find difficult to avoid those words. It'd be fine in articles, essays, etc if it was only because of the repetitiveness, there are three words or more for it, but in longer texts, like novels, it's hard for me to go on pages without thinking my sentences don't vary much in its structure.
There's always stuff to compare or make exceptions and the word but (and variants) have bothered me a lot. I wanted to find an alternative structure for sentences that don't require "but" in it.
How can I reconstruct sentences like these so they won't look like there's something missing if I don't put a but there?
"He shook his head even though the room was dark and she couldn't see him"
"He tried to call, but it was too late."