I'd say the most important thing is preperation. You can work out what 30 markers can be asked based on past papers, then you make sure you have at least 4 paragraphs of evidence that can be elaborated on (you ensure this through the process of understanding). Planning essays is very helpful inorder to understand the structure your response needs to be in your exam.
I think I need to stress importance of understanding for a theory based subject like sociology. The level of understanding you have directly impacts the extent your analysis can be considered good quality therefore your understanding determines the band your answer falls into, analysis wise. Also understanding in very important for long term memory (and therefore knowldge marks) as you can connect your understanding of the content to that in the past. Plus understanding allows you to be able to apply it to different contexts/items (application marks). Since understanding is signifcant you need to ensure that this understanding takes place, and to do this you need to maxamise attention and sources of quality information to allow for effective learning. I'd say focusing on understanding before memorisation is purely whats allowed me to get A* in my first timed 30 marker.
If you have any other questions please ask.