Certainly a polarising filter will help.This can be helped by adding a bit of ND either by a grad filter at the time of exposure or within Photoshop or similar. There is also another trick, that needs either Lightroom or CS3. If you are shooting jpeg, you'll need to tell CS3 to handle jpegs as RAW files. ( It's in preferences).
Load your image. Then go to the HSL ( Hue, Luminance and Saturation) tab. Select Luminance, and then slowly reduce the Blue channel luminance, until you get the result you want. If you need to change exposure, saturation or similar, do this before you attempt the HSL technique, as they will have an effect on it.