Try stopping down -2/3 ...or use an incident light meter.
If you've got a lot of green in the shot (especially in high sun I find), the green channel can hit the end stops and there's no recovering it, not even in RAW.
Overexposure tends to make colours more pastel, tending towards high key grey scale (washed out)
Underexposure tends to enrichen colours (saturate)
...but if the sun is directly hitting your front element, especially if you've got a cheap UV filter...you can get a big reduction in contrast and maybe lens flare. Stand in shade or get a mate to cast a shadow onto your front element and buy a pro UV filter.
Polarising filters might help you, but you'll lose stops.
Hope this helps...but yes, it would be good to see some examples
Steve