I like Duolingo because it is so accessible, however I found that it doesn't bring you up to the level where you are able to speak a language in practice.
For instance, I completed the entire French course but I still can't have even a basic conversation when I'm in France.
What do you think is holding you back? Is it that you don't know how to form a sentence, are you unsure to come up with the right words, do you think the course didn't contain the words you need?
In my opinion the Duolingo course does contain the necessary words, phrases and grammar for holding a conversation. But it may not be enough to understand native speakers at native speeds. And maybe you need to be more confident!
I would recommend listening to French podcasts or videos even if you don't understand them. With subtitles if available.
What was holding me back was:
1. Spoken French goes much faster than the French spoken in the course so I wasn't able to understand most of it.
2. To form a sentence to express yourself in real life is much more difficult than to translate a given English sentence like in DuoLingo.
I agree that to be able to use a language you need to do more than just follow a course like DuoLingo; you have to read books, watch television and most important practice it in real life.
Listening comprehension is the toughest part for virtually everyone.
Forming sentences gets easier once you make the switch from translating sentences into composing them without the intermediate step. That's also possible when translating in Duolingo, you just have to concentrate on formulating the idea in the foreign language.
I made that switch in English first, and I seem to do it by default in any other language. It's much easier that way.
For instance, I completed the entire French course but I still can't have even a basic conversation when I'm in France.