Four things to *definitely* have down:
(a) When it's appropriate and how to use different types of graph paper (log/log plain/log, etc)
(b) Basic error calculations (like the addition/subtraction, multiplication/division, powers, etc as seen on
http://www.rit.edu/~uphysics/uncertaint ... part2.html
(c) Some basic electronics (op amps, high-pass & low-pass filters, that sort of thing)
(d) How to use an oscilloscope and how to interpret the resulting signals
The first two are *easy* marks; generally just recognising a formula or reading off a graph--a few easy points with very little effort.
Good luck! --Ing