Bejeweled 2

alot of the puzzles in cognito mode are the same ones in puzzle mode, either identical or just flipped over. if you get stuck and don't want to use a hint, exit the game (you won't lose your progress) and go into puzzle mode. once there, pause the game and go to the galaxy map. look for the puzzle you are stuck on and go to it. now you can use hints for free and solve your puzzle! i used my cell phone to record the steps of the more complicated ones. i got the achievement at level 13 puzzle 4. (never used a hint.)

I found this achievement rather easy compared to the others.

First unlock the Cognito mode by finishing the Puzzle mode. Cognito is similar to the Puzzle mode but this time you get points for completing each puzzle successfully. Each level consists of three puzzles and if you get stuck you can ask for a hint. Beware, you won't get any points if you ask for a hint (the game warns you about this and asks you to confirm that you do want a hint). Some of the levels are tricky and I used hints to get past them.

You need to reach 50,000 points in this mode to unlock the achievement. You don't need to complete the level you're playing when you hit 50,000. I think I was on level 14 or 15 when I hit 50,000.

The game also saves your progress (like in the Endless mode) if you want to quit to the Main Menu of the game.

This is an extremely easy achievement to get, just a bit time-consuming. Go look up the "Puzzle/Cognito Mode FAQ" by MysticWeirdo on GameFAQs for the solutions to each puzzle in an easily searchable fashion.

A guide of the levels of Cognito Mode, if you want a visual guide. The levels are shuffled, so you might have to search for the one you're stuck on.