This is referring to "Cambridge Essential Further Mathematics - Third Edition"
Pay close attention to all of the notes. Difference equations become very easy once you get the hang of them.
You must understand Arithmetic and Geometric Sequences and Series thoroughly before attempting Difference Equations (although i'm assuming you would have covered that by now)
My main tips for Difference Equations would be
-Being able to identify which Difference Equation corresponds with which Sequence Type (Refer to the diagram on page 330, that sums up everything)
-Be able to generate Sequences on your calculator with ease, and this also includes the Fibonacci Sequence and Lucas Numbers
See the attachment for calculator steps that you must become familiar with (Geometric, Arithmetic and Difference)