Of course there is not one single Swedish style, but still there are some characteristics you can spot.
Simplicity and functionality: Sounds boring? Not at all, there is real beauty to be had in crisp, simplistic and practical designs. Some things just don't need to be frilly or complicated to be interesting.
Nature: Oh the Swedes love nature and so it's only natural that so many elements of nature make it into the Swedish style. Natural wood is a big favourite! Also natural colours like beige and green or flowers, petals and leaf designs. Look closely at the Dala horse for example and you'll find floral shape decorations.
Candles: It is a must for most meals not just for special occasions. Especially in the darker months of the year (and in Sweden they really are dark) candles are very important to create that sense of cosyness, hope and warmth. In summer, candles on the table or in lanterns can help extend those long warm summer nights spent outside with family and friends.
Sentimental: Sweden has a lot of treasured history full of well loved myths, artists, traditions and of course food. A lot of Swedes value their culture and carry it forwards by keeping up all the traditions and passing trades and stories on to the next generations.