So I wasn't sure if people really knew how they were being marked and on what.
Often I hear people are hung up about the small things that don't really have much bearing on the final outcome.
There are four things to take into account.
1 - Fluency and Coherence.
(what you sound like overall) To get a good mark here you don't want to pause and think too much. Coherence means, can you actually be understood.
2 - Lexical Resource.
Knowing a lot of words is great but you need to be able to use them in a correct way.
Depending on what mark you are aiming for will depend on how you should do this. Keeping it simple and throwing in a few big words might be better for you than trying to use a lot of big words poorly as that will effect this part as well as possibly your Coherency too.
Of course, if you want to go beyond 6 then you will have to "go for broke".
3 - Grammar and accuracy.
Complex, simple sentences and using tense.
Keeping sentences simple will obviously help with the coherence factor, hopefully but hinder you here.
Ask yourself. Can you talk about the past and future easily and being that you all probably spent hours in class learning grammar you can use your learnt knowledge to give you higher marks. You will always get questions based on the past and future so don't worry about thinking when you should put them in. Also remember your Hes and Shes, Ss, ings and eds etc.
4 - Pronunciation.
How you say it. The noise coming out of your "pie hole" (mouth).
Please note that accent is not mentioned here. This is about your diction, the way you say it, so if you are having trouble with pronunciation, slow it down and pronounce every word precisely and as you get better speed it back up so your fluency isn't penalized.