To get a few extra points, after every trick, press R to do a revert. Not only will this make it easier to go into a manual but will also earn you a few extra points. Keep doing this in things like contests.

Activate the following cheats by entering the corresponding codes:

CHEAT FUNCTION - CHEAT CODE
All specials in shop - "yougotitall"
All decks (except the Inkblot and Gamestop) - "needaride"
Inkblot deck - "birdhouse"
Always special - "jammypack"
Full stats - "allthebest"
Full air stats - "drinkup"
Perfect manual - "frontandback"
Perfect rail - "balancegalore"
Infinite focus - "shellshock"
Play as Anchorman (Free Skate mode) - "newshound"
Play as Pat the Realtor (Free Skate mode) - "shescaresme"
Play as Christian Hosoi (Free Skate mode) - "hohohosoi"
Play as Colonel and Security Guard (Free Skate mode) - "militarymen"
Play as Dad and Skater Jam Kid (Free Skate mode) - "strangefellows"
Play as Grim Reaper (Free Skate two-player mode) - "enterandwin"
Play as Jason Lee (Free Skate mode) - "notmono"
Play as Kevin Staab (Free Skate mode) - "mixitup"
Play as Mascot (Free Skate mode) - "manineedadate"
Play as Nerd and Bum (Free Skate mode) - "wearelosers"
Play as Photography Girl and Filmer (Free Skate mode) - "themedia"
Play as Skinny Real Estate Agent (Free Skate mode) - "sellsellsell"
Play as Travis Barker (Free Skate mode) - "plus44"
Play as Twin (Free Skate mode) - "badverybad"
Play as Zombie Officer Dick (Free Skate mode) - "suckstobedead"
Vans No Skool Gothic shoes (Free Skate mode) - "hatedandproud"

Unlock the following characters by perfomring the corresponding tasks:

CHARACTER - HOW TO UNLOCK
Bam Margera - Complete all of the goals he assigns to you.
Bob Burnquist - Complete all of the goals he assigns to you.
Daewon Song - Complete the goal he assigns you.
Dustin Dollin - Defeat him as Stevie Williams
Lyn-Z Adams Hawkins - Defeat her as Nyjah Huston
Mike Vallely - Complete all of the goals he assigns to you.
Nyjah Huston - Defeat him as Lyn-Z Adams Hawkins
Paul Rodriguez - Complete all of the goals he assigns to you.
Pro Bails 2 - Finish the game with 100% completion.
Rodney Mullen - Complete the goal he assigns you.
Ryan Sheckler - Complete all of the goals he assigns to you.
Stevie Williams - Defeat him as Dustin Dollin.

If you need to get to a hard-to-reach location in Career Classic Goals, start the challenge, then quit. Go to the part of the level you want to access. Pause game play and select "Retry Last Goal." You should start in the current location.

Note: This might freeze the game when played on an older PSP. Go to City Center and talk to Mike Valley. Do the challenge (even if you already completed it). Ollie through it and when you think you are at the top of your jump, wipe out and quickly pause game play. Select "Exit Challenge" and you will fly for a short amount of time.