The first thing you must know is which days and time of day will be most profitable. Sure, it is possible to win on any day but some days are luckier than others. Go to your local parlor and check the signage, if they are having a big event then you should show up early in the morning, about 9AM or before to grab a good machine that you have scouted.
You can see the last days statistics and in some parlors the last days spins per win statistic on the LED display above the machine. The machines are reset nightly but in the morning especially on an event day "yesterdays winner" will still be set high.
Pachinko Machines are set from levels 1-6. 1-3 lose, 4 win small, 5 and 6 are great. The guys sitting at the 5 and 6 level machines are likely to go home with 70,000 yen or more once their day is done.
Event days have more of these such machines.
Lesson 2 coming soon.