Nothing is tough if one decides to practice it. so continuous practice will make any tough query an easy one.
I wrote a reporting query once that was 700 lines long and visited 27 different tables in lookups or joins. It didn’t do any fancy stuff - just straight whereclause predicates and joining - but it was pretty gnarly and took 3 days to compose, debug, and tune.
It had to run in under 15 minutes on a DB world where the tables it visited had up to 5 billion records each, so it had to be well-tuned - even though it couldn’t help but be icky.
I was very, very careful with the formatting - and the query had about 1000 lines of comments around it so I could remember just what the heck I was doing when - as always happens with reports - the execs wanted stuff to be slightly different six months later