Examiners like.....
.....chocolate hob-nobs.
Seriously, my examiner was fair, mainly because I think I was honest. Understand your limitations, and understand that even with a restricted FI rating, you're not done learning.
Answer the question that is being asked, not the question you want to answer. I knew that I didn't know all of the answers - but knew where I could reference them if I needed to. Don't waffle.
Above all - prepare yourself to the best of your ability. If you make the effort it will be noted by the examiner. Relax. Most examiners are human (one or two I've met that stretch that definition) and most know that you'll be nervous and some allowance for that will usually be factored into their analysis of you're performance.
Enjoy the experience - and enjoy instructing afterwards.