Maybe have a look at http://siteinspire.com/showcase I found this site to have a good collection of well designed sites.

The main area to work on is typography and navigation layout. If you have nice typography and an easy to use navigation, you'll be 90% of the way there.

Another tip is to never use #000 for your text. Try using a dark grey.

Two sites I like the design of are: http://www.thrivesolo.com/ and http://www.bestmadeco.com/