What is the best way to prevent keyboard marks?

"Well on my white MacBook, I've been using the thin sheet of perforated material that the laptop shipped with.

If that doesn't work out for you, I would try one of the many third part alternatives such as

http://www.radtech.us/Products/NotebookS...

Hope that helps"

"Another possibility; look for an optical cleaning cloth (often found at opticians or camera shops) of the necessary size (or trim accordingly). Use this between the keyboard and screen (nice and thin) and doubles as ...a cleaning cloth. Much cheaper than some of the commercial options.

I use a fine piece of leather, which also can be used as a mouse pad on rough/reflective surfaces."

"Get a screen protector from OWC. Been using them for years and they work flawlessly.

http://eshop.macsales.com/item/Other%20W..."

It seems mine collects a lot of dust so I keep a microfiber cloth (think Billy Mays) over the keyboard and when I'm ready to use the Mac I dust everything off and as a bonus, if I wet it a tiny bit I can even clean of my grubby fingerprints. This is also the least expansive of the tips

"Check if the little plastic pads on each top side of the screen are still here and not cut. They serve to keep a small distance when the screen is closed. You can increase distance with added thick adhesive tape.You can try to add two thin little pads on bottom of screen too. Check for the needed thickness with the screen closed to keep the hook grabbed on bottom part.

Eventually try to adjust the hinge height to increase distance to keyboard.

And never put big objects on screen size when you carry the Mac in backpack or use a sheet of hard material (metal, epoxy,..) as separator to avoid any pressure on the top cover."

I have used for years a Kensington Micro fiber cloth - It looks like gray suede, exactly the right size to protect the entire screen... I carry my 15 everywhere and haven't treated it particularly gently, I don't think. The screen looks brand new.