This is a FAQ, just keep speaking and speaking and speaking. Esp with foreigner you guy just keep on conversation and this will take time for you to correct yourself during the conversation. When having problem to understand the other people speech just ask them to repeat or rephrase it, dont feel down or upset when you do like that cos this will ban you from becoming a good speaker.
For relation between speaking and writing I think that sometimes it does have, for instance we can copy soem goods structures and sentences that we have heard the native speakers said, and just practise it by actual way.
This is my opinion, and I always do like that, be hard working and practise practise and practise
Ramin
