On the SQA Website there are NATIONAL 5 PAST PAPERS which you can look at to make sure you have a really clear understanding of what you can expect in your paper on the exam day. There are also mark schemes for each of these papers which you can use to get an idea of how your examiner will be marking you. As well as this (and perhaps even more useful) there are some examples of how other students answered the questions and what marks they got for their answers. Use these to get an idea of exactly how many marks you can expect to get for an answer.
THERE ARE LINKS BELOW TO THESE PAPERS SO YOU CAN TAKE A LOOK...