Also, are you changing the default setting for drop shadows in PSE? They are really set way too high to look realistic. They are set at distance of 21 pixels and the same for the size. It should be set much much lower.
And, are you changing your resolution to 72 when you resize? The Image resize dialog box, all 3 boxes at the bottom should be checked and in the drop down box at the very bottom should be the word "Bicubic". Next put 72 in the resolution box, then in the top 2 boxes put 600 (doesn't matter which box because they will automatically populate the other).
Then tell it OK. Then do your Save for Web with the highest quality possible, keeping the KB's under 150.