Okay. Comparing the corners like Irohazaka. Irohazaka is short stubby hairpins. Akagi has long sweeping corners. Akina is somewhere in the centre. Not too sharp, not too sweeping. Just perfect. Drifty cars like Roadsters, Altezza, FC3S all can perform pretty well on Akina. While cars with grip setup perform well for maps like Irohazaka.

Playing with the gears refers to more extensive usage of the gears. Since you got 6 gears, you've got plenty of speed and turning to play with. You can select a high end Gear 4 or a low end Gear 5 corner, up to your preference. See if you wanna push the car or so then try using a higher gear since you got 6. If its too much under, then switch to a lower gear to corner.
Well, I'm not very good with pickups. But I know HIRA is mad over such things. Basically there's alot of pickups. But it really depends on your opponent. There's no best pickup. You can do a lousy pickup and your opponent does an even worse one. You still win. Depends if your opponent wants to win your pickup with 2nd gear or drag his 4th gear or so on to win you. Then you shift accordingly to match his pickup and counter his win...
Hope that helps.
