To have an extended conversation in your target language you need a good vocabulary which goes beyond basic conversation. One excersize i do with my students is we always make a ord tree for each new subject.
We start by placing the word in the centre of the trunk for example food... then we draw branches fruit veg meats, dairy.drink etc then smaller branches for other foods, we do this in depth until we have associated words like which get further away expanding the subject matter until your have a range of things your can express.... taste,expensive,shopping list,vegetarianism, bitterness, recipe etc
being able to do this means that when you discuss a subject you can recall much more about it rather than saying i like meat, my favourite is beef, you can eventually talk about the farming industry, or how you prefer your teak cooked down to culinary perfection which gives you a better level and allows for more natural conversation flow.
Today i found this great word association site ( i am taking part in a songwriting challenge (for 100 days) and it is a tool that was recommended for song lyric writing practice) i think it might be a useful tool for those with a good general English level to extend their vocabulary use and link different topics which they can already express.