Aggressive Inline Tips & Tricks (GameCube)

The gameplay within Aggressive Inline focuses on completing goals given by talking to characters within each level. While some goals involve gaining a certain amount of points in a specific time, many of the goals involve doing tricks on and off of pieces of the environment (for example: one level asks the player to grind three traffic lights, each one placed at a larger distance and facing a different direction).

Another innovative feature focused on a player leveling system where the player would perform better in different areas of skating skill by practicing them repeatedly. For instance, if the player does many air tricks throughout the course of the game, each successful trick would create points in the player's air trick statistics. When the points reach a certain amount, the player's air tricks will move up a level, making it easier to perform air tricks faster and more efficiently. The same actions apply to grinding, speed, wall riding, skating backward, etc.
(Wikipedia)

Tips & Tricks

Boardwalk: Hidden grind:
When on the roller coaster track, press Up(3), Grind to do a "double grind". You need to be near the tracks, since you are grinding both tracks at the same time.

Boardwalk: Easy points:
After you have unlocked the secret area, you can go to a tall spiral lighthouse. Go inside this lighthouse. The bottom is hollowed out. Get some speed up from the halfpipes outside the entrance then go into the lighthouse and hit one of the walls at an angle. Start wallriding up the middle, continually jumping and wall riding again around the inside walls. When you get about half-way up the inside, slow down your jumping so that instead of climbing up you are just wall riding around in an endless loop. You can get your multiplier up to 199X and do a trick worth 30 million points. This is also good for getting up your Wallri, Fakie and Speed stats.

Go to the roller coaster and jump on the track. Grind either the two middle rails or the rail on the far right. Jump up and down continuously until you decide to jump off. This allows you to complete some objectives on that level and also get a massive amount of points in case you run out of juice.

Movie Lot: Grind the third traffic light:
One of the challenges is to grind two traffic lights. After you do this, a new challenge "Grind the third traffic light" will become available. In order to do this, vault over the bike rack and onto the traffic light. From there you should be able to jump to the third traffic light.

Movie Lot: Secret bowl:
There is a secret bowl in the scientist lab. To get in the secret bowl, grind the top of the test tube towards the joint on the top. When you get close to it do not jump off, just continue grinding until you hit it and crash. When you crash you will end up inside the test tube in a bowl. You cannot get a big combo inside the bowl, but can do a tweaked look back judo with only a small amount of air.

Museum: Ark Of The Covenant:
The Ark of the Covenant can be found in the back area. Go up top the set of three quarter pipes hanging from the ceiling. Handplant the Ark to get a better view.

Museum: Hidden grind:
When on the display cases that are somewhat pyramidal, press Up(3), Grind to do a "double grind".

Extra points:
To do a near-infinite handstand combo, go up to a quarter or halfpipe in any level. Do a normal handstand, rocket, abstract, etc. Hold Down to make the meter go down, causing your handplant to end, but the trick is to keep pressing Grind repeatedly. As you get better, you can do up to a 50 trick combo. Note: This does not always work.

Go up any quarterpipe and do any desired tricks. Do the Cess Slide after your wheels hit the ground and try not to combo it with your tricks.

Find a half-pipe or a bowl and do some tricks. Before you land, do a Cess Slide into a Manual. The trick keeps going and if you have enough skills, you can do it as long as desired.

Hand Grind:
Jump, press Down(3), and grind.

Here's some gameplay footage below (opening):