Take the time to understand the different chart types. It helps if you can get a mental picture of the chart (Mercator / Lamberts / Polar S etc) - then picture the Rhumb lines, Great Circle lines and convergency etc.....then apply the particular maths process. I found it much easier to picture what I was doing rather than just jumping to the calculator or wizz wheel.
I made a little table / picture up of all the charts and lines - then draw that out at the start of the exam - it enabled me to answer lots of questions just from that little drawing and also to check I was applying the correct formula etc.
It will come together..... have faith.
GSS