This is a good one, I like this question.
Typically, I'm looking for the midlane read. Most of the balls in my bag are solid or surfaced because on the left hand side the reaction is normally smoother. I have a Higher Rev Rate, Axis Rotation and Midly Low Tilt, so I get balls to cover boards pretty well. That doesn't turn into strikes. So its been my task to lower the Axis Rotation to get the ball into a roll earlier and through the pins the right way.
With that, Im always looking to either push the ball into the friction at or just before the range finders on THS because most of the time im the only lefty getting inward, or closing my angles and using weaker covers shorter pin to PAP on Sport unless its called for to use something stronger because most of the sport patterns want to push the lefties to the outside part of the lane and keep them square.
As far as adjustments, the pins and where the ball is leaving the deck will tell you most if not all you need to know. 7pins mean my ball is going too long so I need to get it rolling earlier. Hand Position change is most of my adjustment or getting a bit softer at the bottom because the lanes don't transition a huge amount(I avg about 5-7 boards of movement throughout a set). Feet and eye movements are expected so I don't really like to overly hype that because you SHOULD be moving your feet throughout your set.
Typically right after practice is when I make my first move and its maybe about 2 boards per game depending on the variables, topography, puddle(if there is one), ball choice, surface, traffic, traffics ball choices. Also a big key is knowing your equipment and their separations. Its nice to almost automatically know where to stand with the balls in your bag and you switch.
Hope this helps, this is just my moves and thoughts.
