i did this for my assesment task............
the main things to keep in mind......are the 4 purposes of punishment:retribution,incapacitation,rehab,deterrance.................relate these to "resource efficiency,rights of the society v rights of the person, cost, access,.....posssibility of a wrong decision".....etc.......
1 good website to look at is
www.capitalpunishment.com...if i have got this right........try typing in "capital punishment in australia" in google.
u shud b able to get heaps of stuff.
and dont forget to mention the relative legislations,conventions and case studies if possible.