The Rule of thumb to remember is that LESS IS MORE when it comes to packing for your Greek Island Hopping.
You can get by with khakis, light denims, linens, a few pair of shorts and tee shirts for the most part. A light windbreaker, or sweaters may come in handy for the evenings when the sun drops since there is almost no humidity in Greece during the summer months. As far as shoes, leave all the heels at home aside for a pair or two for those special occasions and make sure to bring sneakers, sandals, flip-flops and a pair of comfortable walking shoes.
In addition remember to bring multiple bathing suits, a lot of memory cards for photos and video, a electricity converter if need for your electronics and an adapter for your electronics as well. On your packing list should also be sunglasses, sun protection and a Swiss knife that can come in handy when you least expect it! A good backpack will be priceless on the trip and a money belt is always a good thing to have when travelling abroad.