If you're in Australia and looking for a way to make humanitarian donations that you know will reach their destination, then I recommend donating to the APHEDA Gaza appeal. They have supported many different projects in Gaza and the West Bank, including the el-Wafa hospital which was recently bombed by Israel.
Longer term, one of the most useful projects I've been involved with is the Keep Hope Alive olive harvesting program. Travelling to the West Bank and taking part in the harvest was one of the most useful things I feel like I have done; the planting is harder work, but speaking to those who have done it, even more fulfilling.
Keep yourself informed - here in Australia we have a corporate media which, at best, equates the violence of the occupied with that of the occupier, and at worst echoes Tony Abbott's "We Are All Israeli" line. Sites like Electronic Intifada and +972 are great trustworthy sources. This open letter from Gaza is worth reading too.
And then engage in information making, too - share to your networks, whether social media or around your workplace or communities. Update Wikipedia pages so those who are looking for easy answers don't get the wrong ones.
Go beyond your comfort zone. Unfortunately I work weekends and haven't been able to attend many local rallies personally, but if you can, please do. We don't have the strength of institutional bias or resources that defenders of Zionism do, but we have justice on our side, and when we unite in mass action that narrative can win through. The next Sydney rally is on August 3.