You stole my words.
Grand prix and story mode missions are too easy to finish even on the hardest difficulty setting once you learn to play. I can beat every cup on master and every mission on very hard even without trying.
Here's some basic techniques:
Dash Plates - hitting a dash plate on it's "edge" will actually give you "double boost" producing a higher top speed.
The Quick Turn (QT) - a type of turn routinely used in the max speed ladder. To turn hard right - tap the L trigger, then instantly hold right + the R trigger (while releasingL). The will allow fast and tight turns.
MT - Momentum Throttle
Release the accelerator when at high speed and you will experience a reduced rate of speed loss. This is essential for maintaining high speeds during a race. This technique is also of great benefit before ramps, loops, hills or edges. Boost before a jump and then release A for increased flight speed.
MT Boost When boosting you will notice after the peak of the boost your speeds will drop very quickly, MT boost prevents you from losing those speeds. Right before your boost dies out you want to release gas. You dont want to have gas off to short or too long. You should still see the back exaust lit up just before you resume gas, if your exaust flames are gone you've had gas off too long. If you let go of gas too early you will lose boost speed and you will probably try to resume gas and boost and not get a boost cause you mistimed it, this will slow you down a bit. You will be able to achieve greater boost speeds with this technique and its much better than button smashing the boost. This technique can be particularly useful for chapter 5 in story mode.
MD - Momentum Drift
Release the accelerator and perform the quick turn on banking or sharp turns to maintain speed.
MTS - Momentum Turbo Slide
This is a type of turn that will produce a significant acceleration and increase in speed while it is being performed. Take a turn to the right for example, lean the control stick right and hold L&R together but instantly release R and A. This should leave you holding right+L. For a left turn you should be left holding left+R.
MTRS - Momentum Turbo Rail Slide
This is a variation of the MTS move but is usually used as a very fast finishing move along the rail of the track down the finish straight. To perform this move, get very near a rail at the finish and MTS against the rail. Most top videos use this technique.
More techniques:
http://www.mrfixitonline.com/viewtopic.php?t=463
Me beating staff ghost over 25 seconds on Aeropolis Dragon Slope.
http://www.youtube.com/watch?v=qSWyxzp8Ns0
F-Zero GX is a deep game and that's why i love it.