Is it your first website design? Color combination is good but the site is not looking as a professional Article Directory.
It's helpful with new wordpress sites to put up posts for a few weeks, then make design tweaks to see how your writing incorporates into the design.
Needs some graphics - since its a travel site why not some photos of Vietnam? A logo would be nicer than 'article directory'
These are great points and was pretty much what I thought when I saw it. Instead of "Article Directory", possibly "Tips when you travel", "Safe Travelling" or something related to what your articles will feature.
Like everyone else has said, the site is rather blank. Also the links at the top should not be green since it really clashes with the lighter green color.