This is a quick walkthrough describing how to beat Mario 64 DS in a simple list type way. Although this can be used separately, it is best used to determine which order to get the stars, then checking the full walkthrough for the method. This sounds complicated, but the idea works well enough in theory!
Start the game.
When outside, catch the rabbit to get a key.
Unlock the door.
Get star 1 in Bob-omb Battlefield.
Get star 2
Get star 1 from the secret slide.
Get star 3 in Bob-omb Battlefield.
Get star 1 in Whomp's fortress.
Get star 2 in Whomp's fortress
Get star 3 in Whomp's Fortress
Get star 2 in the secret slide.
Get the star in Sunshine Isles.
Get star 4 in Bob-omb Battlefield.
Get the rest of the stars in Bob-omb Battlefield.
Beat Bowser, also gaining the two stars from his level.
Beat the rest of Whomp's Fortress.
Hit the red switch
Beat stars 1-6 in Cool, cool Mountain.
Beat stars 1-6 in Jolly Roger Bay
Enter the courtyard
Collect the eight Red coins
Beat the Battle Fort level
Go into Big Boo's Haunt and beat stars 1-5
Beat star 6 of Big Boo's Haunt and star 6 of Jolly Roger Bay
Beat all levels in Lethal Lava Land
Complete levels 1-3 in Hazy Maze Cave
Complete stars 1-4 in Shifting Sand Land
Beat levels 1-2 in Dire, dire Docks
Defeat Bowser in Fire Sea, also gaining the two stars in the level.
Unlock the 3rd Floor
Complete all earlier levels that require Wario
Finish all of Goomboss Battle.
Complete Snowman's land levels
Complete Chief Chilly Challenge once and for all.
Finish Wet-dry World
finish Tall, tall mountain
Defeat all the levels in Tiny-huge Island
Complete the stars in Behind the waterfall and Secret under the moat
Complete all secret levels missed prior.
Go to the 4th floor.
Nab the two stars in over the rainbows
Complete all of Tick, tock, clock
Finish of Rainbow Ride
Grab the two stars in Bowser's level.
Grab the white rabbits for the final star.
Defeat Bowser in the Sky.
Unlock all the minigames
Shoot to the roof.
After all that, relax!
After you gain all 150 stars:
You can blast to the roof in the cannon, gain 3 extra lives and catch Luigi's last and final rabbit. The penguin you race on the ice slide is much larger making the race harder.
Go to the walkthrough:
View cheats, the essence of game playing genius!