Island hopping !!
Skip over the heavily fortified like Rabaul and Truk.
Central Pacific:  Gilberts\Tarawa the Terrible (1000 US marines die in 72 hour battle for a strategic atoll.)
Then Marshall Islands (Eniwetok, Roi-Namur)
Gilbert chain next:  Saipan, Tinian, Guam
Iwo Jima
Okinawa
Hollandia, Leyte, etc. in South Pacific