First of all whenever you see tuning guides make sure they have credibility behind them. That guide that was posted is a good starting point but the damper section is very very dumbed down and won't really help you.
A big misconception about tuning - making something stiffer reduces weight transfer. This is false. The only things that affect how much weight transfers are total weight, center of gravity location, and track width/wheel base. In pCars we can't change 2 of those so all you have is ride height and weight bias (mostly just front to back) to adjust cog location.
Keep in mind tuning suspension is all about weight transfer. A stiffer spring, roll bar or damper will transfer weight faster in the direction the weight is moving. This is because the weight reaches a steady state faster because it has less distance to travel. So if you stiffen the front springs and your turning left, weight will transfer more quickly to the right resulting in more understeer. Why does this create understeer? Tires work the best when the axel their on is evenley loaded. While cornering this means we want to keep weight on the inside wheel as long as possible. As an example if car A turns left and the front right wheel has 300lbs on it and the front left wheel has 150lbs on it the car will have less grip than car B which has 250lbs on the right and 200lbs on the left. This is because car B has its weight more evenley distributed between the 2 wheels. The same concept apples to the rear wheels as well. When you soften something in the suspension this is effectively what your trying to accomplish, more evenley load distribution. This doesn't mean go full soft on everything because the extra body roll has to be considered among other things.
If you have trouble on corner entry or exit, I would adjust dampers first. This is because dampers react quicker to weight transfer than springs and roll bars. Be warned dampers are by far the most misunderstood part of tuning and require a lot of time to fully understand.
http://www.ozebiz.com.au/racetech/theory/shocktune1.html
Steady state cornering or cornering where the weight transfer is complete (the middle bit) is controlled by springs and roll bars since no weight is moving dampers can't react. Note that not all corners will have a steady state.
If you have a lot of front grip but not much rear grip don't try to take away front grip to compensate for the rear. Always try to add grip on the end of the car that has less. Usually this means softening something.
Back to the original question
. I wouldn't say small adjustments make a big difference, unless we're talking about aerodynamics. If your trying to learn and understand what a certain adjustment does you may need to make a big change so the effect is clear. You should only adjust one thing at a time unless you are familiar with tuning, then you may be able to adjust multiple things at once since you know what the effects will be.
It's better to ask questions and understand why what does what than just what does what.
