Jones trailed 7-2 after the morning session against four-time champion Selby having felt “absolutely shocking”.
The world number 19 recovered later in the day but had no answer as Selby claimed the three more frames required to seal victory.
It was a disappointing exit for the Welshman who came through qualifying with the aim of going one better than his appearance in the final two years ago at The Crucible.
Jones added: “I missed a few easy balls and it turned into a bit of a nightmare.
“I wasn’t nervous or anything coming here, but I missed a few balls and in this venue it can get on top of you. You just want to sneak off out of there but you have got to stay and keep going through it.
“Playing someone like Mark, a Crucible specialist, one of the best players ever, you need to settle down early and if you don’t, what happened happens.
“I felt good in qualifying last week but that was a week ago, I could’ve done with my match being Saturday or Sunday and I felt I had completely lost it in the last week. I’m going to go back and start practicing really hard.
“My life away from the game has been a bit of a mess at times, my practice has been pretty bad in the last five or six years and when I got to the world final it was a bit of a miracle, I’ve been kind of winging it.”