I love doing jigsaw puzzles. When I was very young we got them at the gas station. Turns out they were Fisher Price and they had one picture with all the pieces in place and a hidden, related picture underneath-loved that! I also remember my first big puzzle-Springbok, circular, a rainbow of jellybeans, spelling out 'jellybeans'. I must have put that together more than a dozen times.
Recently I've worked on some tough ones that friends have gotten me.
Like The Watering Hole by Alex Beard. The finished puzzle is beautiful, but it is hard for its size. I didn't even attempt it without consulting the picture!
Also difficult for the number of pieces is The Baffler by Chris Yates. This is only ~60 pieces, and with the picture is pretty fast. But if you just go by shape...it took me over an hour!
And finally, someone gave me a puzzle of a Jackson Pollack. Holy cow! Even with the picture to consult this is hard. I had to use a combination of shape matching, color matching and looking for the location of the piece by scanning the picture. I have never loved Pollack, but after spending so much time looking at it, I have decided I actually like the outer parts of this painting where there are not as many colors involved. This took about a week, and each day was way more time than is reasonable.
Not a lot of yellow, so I started there.
moved to blue
Then you can look for connectors or pick up a piece and scan the picture for where it belongs.
Using shapes is effective at this point since there are so many nooks and crannies.
See the organized tray in the back-it is mostly by shape at this point.