You're right robomatic. Certain patterns occur over and over again. After a while they become recognizable no matter which way the puzzle box is turned. The end is in sight. One of the patterns is that the potential boxes for a given number will run left, center; center right and all three open, all in one line of nine box squares. You can count on this. The orientation may be top, middle; bottom, middle and three open. The three open may be in a straight row or down up down , or up down up, etc. but it's always a stopper that means you have to go on do some other number and come back after you have eliminated one or two open boxes.

My method is to start with 9 and quickly scan for obvious numbers then on to 8 and down to 1. Then I do it again. I will spend no more than 2 minutes at this. If it is particularly difficult I will take a third spin down the numbers then I will start with the most numerous number available, determined at a glance. I will scan a line in a three nine box series for the possibles. I keep my eye out for three in a row in any box and that means that a different number in one of the other two boxes has to go above or below that row and the third instance can only occupy the last three row space in the third box of nine.. I hope that make sense. If you've work with them for any time it should speak to you and really, it's kind of self evident. At any rate, my trick is not not linger over any one number as it will eventually become apparent on its own as you progress.