Below I will list my scores for each level I completed with 3 stars.
First Steps - 1653
Fly Momo Fly - 3538
A Challenge - 4695
City of Xio - 10070 (9000 should be enough)
The Gate - 6449
Guaka - 12900
Freeing Fry - 3458
A Friendship - 4057
Kuton - 5376
Some general tips:
While time and the bonus you get from it can be important, in some levels its much more important to get as many little stars as possible (including secret ones).
Completing challenges will help increasing your score. Try completing as many as possible if you only manage to get one or two stars.
Try to die as few times as possible in a level and make sure to get bonus health if you lose a life.
If the achievement is not unlocking even though you gained 3 stars in every main level, play one of the bonus stages and fail immediately. It should unlock afterwards.
Level specific tips:
A Challenge - hit the target in the second area of the game, then use the lane on the left side to go back to the previous screen and shoot the little fella across the bridge for 1400 points. There are more stars on the 4th and 5th screen.
City of Xio - Get as many stars on the flying section as possible. There is a secret star hidden on the right side near the end of the flying section worth 500 points. At the end of the level you need to hit a switch to open the final door. Hit the switch, then try to get your ball to the very right of the screen, where a secret door will open for another ~400 points.
The Gate - On the second screen, there is a switch on the right hand side, which will lower a platform on the upper left. On the next screen hit the switch then use the opening on the left. Finally on the next screen, there will be two secret opening in the walls that need to be hit three times.