I'm completely addicted to this game.
My highest score is 330,600 but right now I'm at 324,250. I have a friend who's at 369,850 so I'm really trying to beat her, but I don't think it'll happen. I do think it's easier since they changed it; before that I'd only hit 250,000 a few times, now I can do it daily. I can also now occasionally get up to 7x or 8x, before I only hit 5x or 6x. My friend's scores have all shot way up too on average.
I always start before the go, I don't pick up the mouse, I click (and hold down) then slide it to the color I want to swap it with, I try to find swaps on the bottom of the screen, when the screen turns that funky yellow I try and swap as many 3 combos as possible, this seems to make more jewels explode (it's best if you can get them to explode near a 2x, 3x, etc), if you have more blinky jewels at the end you get a bigger last hurrah, and if you can use one jewel to complete two sets at the same time it's better also. Oh, and don't be afraid to use the hint button, you're not penalized for it.