Well, I have been using Duolingo too and though it is tremendously useful, it also restricts your mind from thinking beyond translations. I generally first think of the sentence in English and then translate it in my mind and speak the corresponding sentence in German. Takes a bit of time
I suggest you read some Kindergarten German books or German short stories which are really useful in adding regular words to your vocabulary. Google them and you'll find many on-line for free (I have)

Hans Wilhelm's books are available online as well (
http://www.childrensbooksforever.com...s/German1.html) They are picture books meant for kids but hey, they help to learn
Happy learning