One of the best ways to help improve fluency is to speak about subjects you know well. Speaking about what you know, you'll tend to take more risks as you've probably picked up related vocabulary along the way due to your interest in the topic. Even if you don't know all the jargon, you'll certainly be able to try out some new vocabulary you'll have seen on numerous occasions. Speaking about something you are "expert" at builds confidence because you won't have to search for the right terminology.
This boost in confidence can lead to a virtuous cycle: The more I speak, the more I'm willing to make mistakes, the more my English improves, which leads to a willingness to speak more, etc.
The Virtuous Cycle
A virtuous cycle is a process through which you steadily improve over time. Think of improving your English fluency as not going from point A to point B, but, rather, like a spiral that grows over time as in the graphic. You'll start off slowly, but you'll expand, you will become more fluent, which will lead you to want to speak more and so on. The key to improving fluency is to grow slowly over time and take time for the process.
It doesn't happen over night, so you need to have the right attitude: I'm going to make mistakes, and I'll learn from them.
Conversations are a River
Good conversations flow like a river. They go from this topic to that topic, nothing is forced. If you listen to closely to yourself, or are constantly thinking "Is this right?", you'll block the flow of the river. It sounds simplistic, but I've noticed it to be absolutely true. Even if you have difficulties finding the right words, take your time, find the words and participate. Don't criticize yourself.
Here's a way to think about improving your fluency through conversation.
1.Trust yourself to speak.
2.Make a number of mistakes, but continue the conversation.
3.Listen to your partner speak on the same subject.
4.Notice differences between the vocabulary you've used, and the vocabulary your partner has used.
5.Compare the differences and consider the following questions:
(1) Can you pick up any new vocabulary?
(2) Were there any differences in the way your partner used the expressions?
(3) Why were there differences?
(4) Were they differences in grammar usage?
6.If you are speaking with native speakers, pay special attention to small things like the preposition used in a phrasal verb.
7.Start to change your own expressions using the knowledge you've gained.
This process takes place naturally, but thinking about this process consciously will help you make it part of your English learning process. Once you've done this, your English will improve much more rapidly. However, it takes time, so have patience and trust yourself!
I Don't Want to Speak until I'm Perfect OR I'll Make Too Many Mistakes!
Many students who are unsure may feel like they shouldn't speak until everything's just right. Or, perhaps they feel that they'll make too many mistakes. For me, there's no such thing as too many mistakes. The more mistakes you make, the better - if you pay attention.
Attitude is Everything
If you worry about making too many mistakes, you're not paying attention to improving your English. By taking your attention off your own mistakes, and comparing your English to your partner's you'll become more relaxed and better able to speak English.
Putting the Process into Practice
Choose a topic in which you are an expert. Something you really love to do, a place you enjoy visiting, anything you're interested in. Find a partner, and talk like the expert you are. It'll build confidence and you can put some of these ideas to practice because you'll be more relaxed.