Often when we write in English it is for an exam or another stressful situation and we concentre on the task that we must do. There may be a time limit or other pressures which mean we don't want to waste time.
Unfortunately this means that we write down the first thing that comes into our head, no matter whether this is the best thing we can write. On the other hand, when we are in a classroom doing grammar exercises we are more than capable of writing an advanced sentence or two!
So, how do we make sure that what we write in an exam or another high-stakes situation is actually our best work? Well, like with other things in life, it comes down to practise. You have to start with simple sentences and gradually make them more complicated and advanced, until you get a really good advanced sentence. You then have to repeat this exercise, becoming faster and faster.
I have made a short video to demonstrate the idea and it is available on our YouTube Channel here:
Once you have mastered this technique it should become a mental exercise that you do while writing. In an exam, when you have an idea, pause and think about how to reform it; how to improve it!
Below you will find a downloadable PDF (and key) to get you started. It gives the examples from the video and a few others for you to try. But don't stop there, once you have the hang of it, create your own exercises. Good luck!