1. DO NOT TOUCH THE NOS, you do not need to modify it at all, most people do so thinking it helps but really it doesn't.
2. Final drive. The final drive determinse how much power goes to the wheels. The lower the number the less power, the higher the number, the more power, if you have a RWD car like a ferrari novitec rosso, then you want the number to be lower and then you will not burn out, but if you have a 4WD car that does not burn out, add a bit more power and when you see a little bit of tire smoke, you are good to go. The thing is tire smoke is an indicator here, if you have lots of tire smoke, you are adding to much power, if you dont have tire smoke, that might mean you dont have enough power, so you want a small quick burn out and then none at all during first gear.
3. Gears. The number on the gears indicates how much power is used in each gear. So if your first gear is 4.375, that means it is going to use 4.375 out of 4.375 power on that gear, and the second gear would be for example 3.5, that means it will use 3.5 out of 4.375. You might ask why on earth then does the game not let second gear be more power than first. Well if you know how transmission works and its purpose you would understand. The point of gears is to use less power to accelerate with each gear. so that is why there is less power each gear. Now you might have noticed the stock tune grows exponentially from bottom to top, that is how it should be, it should be a very big arc to the right or it should be more of a straight line. you don't want any jagged parts.
That is all there is too it, there is no perfect tune because each car is different, even if they have the same upgrades, because each person drives differently and you cant use the same tune for 1/4 and 1/2 mile races.
If you are tuning for quarter mile and you don't pass second or third gear, that is not good, for quarter mile tuning you want to get through as many gears as possible.