Jet Grind Radio

Note: This game is also titled Jet Set Radio.

Love Shockers gang:
Successfully complete all Shibuya-cho levels with a Jet rank.

Noise Tank gang:
Successfully complete all Benten-cho levels with a Jet rank.

Poison Jam gang:
Successfully complete all Kogane-cho levels with a Jet rank.

Goji Rokkaku:
Successfully complete all the Grind City levels with a Jet rank.
Information in this section was contributed by Mark Porga.

Alternately, complete both the story levels of Grind City in Jet.
Information in this section was contributed by jesusfreak12.

Garam:
Successfully complete all of Garam's challenges.

Gum:
Successfully complete all of Gum's challenges at the start of the game.

Mew:
Successfully complete all the Benten-Cho levels. Mew will then challenge you. Win all three of her challenges.

Pots (the Dog):
First, unlock all the bonus characters (Noise Tanks, Poison Jam, Love Shockers, and Goji). After completing the game, play the "Monster of Kogane" level before "Benten Boogie". After completing those levels, a Noise Tank will challenge you after Chapter 2. Defeat the Noise Tank Challenge and you can play as Pots.
Information in this section was contributed by Jeff Ramos.

Skate backward:
Press Down, Up while skating.
Information in this section was contributed by MEWSMDBZ.

Select characters faster:
Hold R at the character selection screen to cycle through the players faster.
Information in this section was contributed by Aclark73.

Hint: Plague of frogs:
Start a new game. Complete Shibuya GG with a Jet ranking. Then, complete Love Trap with a Jet ranking. Finally, defeat the Love Attack with a Jet ranking. You should not be able to complete any more Love Shockers levels. After this, complete Benten Boogie with a Jet ranking. If done correctly, you should have a plague of frogs in your garage.
Information in this section was contributed by aragorn.

Hint: Jet Technique trial:
Information in this section was contributed by MonkyFun.

Stay skating in the zone you start in. For example, in Shabuyo-Cho you start at the bus terminal. The zone you start in is usually the easiest one to get the most points.

Instead of just messing around, find a way you can make a circle that you can just skate around in, getting points. For example, at the bus terminal, grind along the railings, board slide on the billboards, and jump to each obstacle until you get back where you started without falling. From there, go around and around repeatedly until you fall off. You will get hundreds of points.

If you are in range of a graffiti location and you have at least one can, spray away. You will get 500 points just for that.

Do not stop skating. You only have a limited amount of time.

Hint: Jet Graffiti trial:
Information in this section was contributed by MonkyFun.

Spray every single space, even the green arrows.

Use a character with a high graffiti gauge (Gum, Parana, or Yo-Yo). It will be harder, but you will get more points.

Hint: Jet Crush trial:
Information in this section was contributed by MonkyFun.

Do not bump into your rival. You will get hurt and slow down. Get out of your rival's way -- if they slam into you, you will the one that will get hurt.

Find ways of getting by your rival without getting hurt. You can jump or dash (both maneuvers if executed correctly can help you out more than you would suspect).

Find shortcuts. Some are obvious and some take a little more experimentation For example: In Shabuya-cho while racing Beat, before jumping of the bridge into the half pipe, get ahead by grabbing onto a bus.

Do not stop. One second could be the difference between a nitro and a jet. Timing is everything. Fail on one thing and you can get very far behind.

Hint: Street Race: Beat:
As you begin to challenge him, race to the center rail and grind. Use X repeatedly and jump when needed. If you are an expert, you will be able to jump on the left side rail. For the rest of the race, just jump the cliffs and use boosts.
Information in this section was contributed by Jammin209.

Hint: Taggers Tag: Poison Jam:
After the small race of following, the group will separate thinking they will trick you. The first member will jump as the rest keeps going. He will keep running around the bottom of the ground. This goes for all the members. Just run into them and use graffiti. You can dash in front of them to do major damage.
Information in this section was contributed by Jammin209.

Hint: Flag: Rapid 99:
Go for the first flag and head towards the dragon tower. After the first flag, Rapid 99 will go after the second one. As soon as they get the flag, they will take about a minute to return, giving you enough time to get the third flag (where you entered the level), fourth flag (under the tower), and last flag (on top where you first saw Rapid 99).
Information in this section was contributed by Jammin209.

Hint: Street Race: Cube:
The first time you grind, you will see two poles (red and blue). The blue pole is easy and the red pole is twisted. The red is better, because you will go faster and will not jump. Cube will be stupid enough to go on the blue pole and fall. Do the grind red technique the rest of the race and humiliate Cube to join you.
Information in this section was contributed by Jammin209.

Hint: Street Race: Future Site Of Rokaku Expo:
All the races seem easy. However, your opponent will be faster than you. Grind as in the Beat race and you will get extreme points and speed. This will work for the first shot at the ball.
Information in this section was contributed by Jammin209.

Hint: Panties:
Select Gum or Mew, and then choose Jet Technique or Graffiti (preferable) Technique. Select one of the three Tokyo-to streets. The ones with greater chances of this trick working are Shibuya and Benten. Head to the half pipe area of whichever one you selected. Have the camera generally stay in one area, instead of following you, as you go back and forth (as if watching from inside the half pipe). Gain enough momentum so that you can roll past and above the camera without hitting the top. If done correctly (and with some luck) you will be able to see Gum or Mew's panties.
Information in this section was contributed by Morter.

Hint: Crash helicopters:
Crash helicopters by grinding on objects that go close to them and spraying the windshield. You might a the green arrow near the windshield.
Information in this section was contributed by MonkyFun.