I've been seeing many people wearing tartan scarves all over the UK. Perhaps the trend has spread across the world?
Here are some outfits I've put together (using polyvore). They're what I've seen people wearing. Similar to those outfits I've been seeing on the street.
Link to the set itself: http://www.polyvore.com/htw_tartan_scarves/set?id=150475323
Tartan is a very versatile print. With Scottish influence the print is timeless. It's a fabric that has been one for school uniforms. Not just kilts but, now a whole range of other items of clothing.
The most popular today being the Tartan/Plaid scarf.
Hope the outfits above help you style these scarves.
I'd suggest wearing them with block colours or take the colour in the scarf and add pieces the same shade to your outfit. Nearly everyone I have seen with a plaid scarf has a muted tone over sized look.