practice as muchas as possible. Try to think in that language. Practice to make comments to yourself in that language to describe things you see or listen while doing other stuff. This way you can train your skills in improvisation too.

Why don't you start by "talking to yourself". I mean, you can start by speaking out loud what you are doing and what you are going to do. Then, you could start exchanging language with someone else. 

I also recommend you booking "Conversation Lessons" when you will be free to practice the language and the teacher will be there to help you whenever you need him/her to. 

Hello! Im here with the same goal like you that is to improve my Engish. To my experience, when we are nervous, we will find how tough to respond even a simple question. We should practise speaking more frequently, as much as we can. Shouldn't think so much about grammar in this stage! Trying to use english everytime, everwhere ..

Be confident!

To improve your speaking skill first of all you should improve your listening skill. May I ask you, if you watch an English movie how much percentage of talks can you understand?

If you follow Mrs:Edna's advice then you can't improve your listening skill. So when you face a real situation to speak English you may have to beg for pardon many times.