Maximizing Points
You get very few bonus points for finishing a level quickly, so take your time. Make sure to use those extra seconds, especially in early levels to find as many bonus collectibles and power-ups as possible; you will need them in later stages.
Clearing the Corners
The best way to clear boards is to do it with a pattern. Start in one of the corners near the outside of a puzzle and make your way around clockwise. You will be able to see when you are next to a power-up or artifact because some of the icons bleed over onto their neighbor tiles if you look closely. Keep an eye out for those gold pixels bleeding over and unlock them right away.
Replayability
Once you have mastered all 77 levels and rescued all of Poseidon's magical trinkets, you can go back and try it all again in a bonus mode where all of your treasures have moved around and there are a few more enemies in each board.