Achievement Unlocked

Completed Radiator Springs and unlocked Ornament Valley, and got the sticker to prove it

Guide
Once you've completed all races in Radiator Springs you will unlock Ornament Valley. Basicly storyline.

Won the Rustbucket Race Series

Guide
This you will find in Ornament Valley. Simply finish first place in each race to unlock this.

Completed all nine levels of Fillmore's Fuel Frenzy

Guide
There are three levels in each three areas. This is not a race against the other cars, so don't bother racing them. Simply pick up gas cans and make it for two rounds each. Once you get the message "You won" you can finish the race by going to a complete stop.

Completed all six levels of Tractor Tipping

Guide
In this you simply drive around tipping tractors. Avoid Frank and spotlights. I also recommend turning off automatic camera angle setting. This way you can control the camera angle yourself. These levels are scattered in all three areas.

Completed all seven levels of Ramone's Rhythmic Rumble

Guide
Simply score enough points each round to win.

Beat all seven levels of Ghosting Mater

Guide
Probably the "hardest" achievement in this game. The "move the stick to the left to turn right" and "move the stick to the right to turn left" really messes up your brain. Simply turn your stick upside down. Makes things alot easier to makes turns.

Finished in the top three of the Monster Truck Waypoint final

Guide
It says you can make it in top three for this achievement, but for the completion of the game you have to make it first place.

Completed all nine levels of Doc and the Law's Race 'n' Chase

Guide
You and your opponent will have finish lines in opposite sides. Once the race starts he will race against his, so you'll have to tag him and quickly turn around and head for your finish line. I cheated on this and activated unlimited boost. Made it a lot easier ;)

Completed Ornament Valley and unlocked Tailfin Pass

Guide
Once you've completed all races in Ornament Valley you will unlock Tailfin Pass. Basicly storyline.

Unlocked all 8 of McQueen's new paintjobs, available at Ramone's House of Body Art

Guide
See map for locations.

Paintjobs are found in Radiator Spring, Ornament Valley and Tailfin Pass.

Unlocked all 8 of McQueen's new wheel sets, available at Luigi's Casa Della Tires

Guide
map

Wheels are found in Ornament Valley and Tailfin Pass.

Found the parts necessary to construct Monster McQueen

Guide
map
Found in Radiator Springs.

Found the six parts necessary to construct Monster Mater

Guide
See map for locations. These parts are marked with blue dots.
During gameplay you will offer Mater to search for parts for him. You will have to use a metal detector to find them. Simply press LB to activate the detector. Once you've reached the area where the parts are you have to dig them up by pressing RB. Using a map for these aren't actually needed since the metal detector will show you the way anyway.

Won all four race in McQueen's new Racing Stadium

Guide
These races take part i McQueen's racing stadium and will be marked with a white star when available. This stadium is found in Radiator Springs. The forth race will be available after a credit roll when you're done with the storyline.

Won all nine road races, three in each of the three main areas

Guide
There are three road races in each area, and they will be marked with a white star.

Won every event, collected every Bolt Banner and earned every sticker

Guide
For this you have to win all races and side-missions in first place. Some of the races and side-missions will earn you stickers by coming in first place. Bolt Banners are earned when winning races as well.
To summon it up: win EVERYTHING in first place.