I think of how I can capture the enemy king.
What are you thinking when playing chess?

Well, he said that every game he plays he says to himself normal threating questions for an example; "Is my oppenent threatning something?" and I always thought masters don't do that, instead they actually do!
i totally agree with you dude. I once played an expert ,But instead of mumbling his words to himself he was literally talking aloud (even saying his counter plans) which gave me the chance to hear all of em and hold on till the endgame. And after the game he quipped "Bhoy you play well". I said " No, i listen well" . From then on i tried using his approach but on the silent method though. :). Funny but It really works.

On my turn:
Why did opponent move piece? What new moves are open to him with that piece? Which of his other pieces are now unblocked by that piece?
After my defense seems solid enough:
What pieces/squares is he no longer protecting? How can I lose my Queen fastest? And then I proceed to lose queen and the game.
In all seriousness I mostly play with just the first group above, a defensive mindset. I think I miss more opportunities, than allow my opponent to easily pick me apart. Which because of my blown opportunities, he picks me apart anyways.
What do you think about while reading?
Do you sound out each word? Do you check if individual letters can be combined for a new sound e.g. ch and sh?
Do you read a word and ponder its meaning?
Maybe a whole sentence at a time? Maybe how that sentence fits in with the paragraph? Maybe how that then relates to the overall message of the whole piece?
If you follow my metaphor that is :)
Veteran readers (titled players) can still stumble over a word, mistake homophones, and otherwise make basic errors. But when in form, an enormous amount is handled by the unconscious. Everything useful you and I can think about a position after 20 hours of thought is as easy and instant as exhaling to a GM.
What do players think? We go through our habitual check lists, looking for squares and familiar themes and undefended pieces, all the while offering them up to the unconscious which spins and whirs and offers back tips and cautions from past lessons. Basically all players are thinking the same way when we play. Just like 6 year olds and fully literate adults alike transform scratchings on paper into thoughts and ideas...
but what's really going on, what's really interesting, the processes that can separate players across the span of nearly 3000 rating points, and the explanation your question likely hopes for, is something we can't really describe to eachother in detail. It's the enormous benefit of experience and lessons ingrained after countless hours of analysis.
Sometimes I think, "What was I thinking!!."