Advice on Oz travel Summer 2015 pls....

We're looking at travelling to Australia and New Zealand for Summer 2015 (yes, school holiday peak period
) and I wanted to ask for some advice on how/when to book the best price flights for the trip.
Specifics are; Departing for Oz at end of July/start of Aug 2015, then returning some 4-5 weeks later. I don't have FF membership with carriers other than VAA (although wife has relatively minimal BA status).
Sooooooo, how to get to Oz and back as economically as possible - when is it best to book and does anyone know any secrets of the "how to get to Oz in peak travel period for nine-pence
?
I don't want to travel on air china anything, as I'm not sure we'd get there and back in one piece
) !
All advice welcome...
Thanks as always!
Viz.

Specifics are; Departing for Oz at end of July/start of Aug 2015, then returning some 4-5 weeks later. I don't have FF membership with carriers other than VAA (although wife has relatively minimal BA status).
Sooooooo, how to get to Oz and back as economically as possible - when is it best to book and does anyone know any secrets of the "how to get to Oz in peak travel period for nine-pence

I don't want to travel on air china anything, as I'm not sure we'd get there and back in one piece

All advice welcome...
Thanks as always!
Viz.