I know its hard i struggle too.  Its all about trial and error,  finding out what actually sells on Ebay.  Once you get an idea dont forget to do your completed listings search in Australia to see if the item is selling and what its selling for.     Also if you dont have a store IMO ( and others may disagree)   make sure you are pricing just slightly lower then your competitor so that people can find you at least under lowest price search.  Also make sure you do some auctions, its another way to get your listings actually viewed and then people actually see your other listings and may buy full price if they miss out on bidding or need the item right away.         The trick is to get your listings viewed and that can be really hard if there are pages and pages of similar listings above you.