Hello Maya, 

• Time is very important. Practice making models in time limit.
• Use as much items given as you can in the model. But use only where they are required.
• Watch youtube videos to get inspired and practice as many models as you can .
• Do not panic before , during , or after the exam.
• Focus only on your model . Do not pay attention to what is happening around you or what others are making. And never change your ideas after seeing what others are making.
• Use the first 5–10 mins in visualising what you wanna make out of the given topics.
• After receiving the materials just see the packet from outside and analyse the materials . Dont open the seal until asked to do so.
• Keep last 10–15 mins for writing the write-up.

Hope this helped you!!

Thank you