I have been using similar tickets in the past few years and achieved WP this past year (thanks to routing help on FT).

As a starter and time allowing:

-within Europe i do at least LHR-DXB-LHR as a SC run
-from Aus/NZ if I was you I would do MEL-CBR-CHC-SYD-JFK....6 NA segments....-Europe
-within NA make sure you do most of your segments in the 1001-2700 range, only longer one in NA is SFO-BOS which is 2702 and that can be your transcon
-if on DONEx in NA you fly in F and get miles and SCs (although not much diff) for F and not D
-NA-Europe should be LAX-LHR or the like - ie west coast NA to Europe
-Europe to Aus I did LHR-BRT-HKG-MEL to maximise SCs and miles. SInce you need to be in PER and SIN why not LHR-NRT(BA)-HKG-SIN-PER

Good luck and have fun - planning a RTW is almsot as much fun as doing it :-)