When thinking about make-up, your starting point should be the script. This should be in your mind at all times - you're designing make-up for the play, and what you do should support the piece.
Find out what the actor you are designing for actually does in the drama. Their character needs to be shown in their make-up.
Make full use of your school/local library and the internet to obtain examples of make-up types and characters from other performances. A historical character and a modern character will need very different styles of make-up. You could start with the make-up page from the galleries section for some ideas and references.
Different make-up products are applied in different ways. Few actors use 'grease paint' these days, but you can use it if you like.
If your design is for a fantasy character, think about colour, remembering that different colours symbolise different ideas. If the lighting designer is using coloured gels, experiment with how your colours are affected by this. Red, for example, under red lights tends to look washed out, while under blue lights it starts to look dark, almost black. So choose colour with care!
Make a series of designs using a make-up template, and keep notes that will show the progress of your ideas.
Make sure your photos show the progress of the make-up session, so the examiner can see your attention to detail.
Think about creating a slideshow presentation with the major stages of your work outlined. This is a good way to organise your thinking too. To learn about making a slideshow presentation, check out the Presentations Revision Bite from the Bitesize DiDA section.
Check that your notebooks are ready for the examiner, with those designs and images not used in the slideshow presentation. Perhaps you could mark your best pages?
You need to have ready at least two final designs for the costume and make-up and designs for all other costumes and make-ups used by each actor.