Hamas style:
* Refuse to recognize Israel. Remind the world that the establishment of Israel in 1948 was accompanied by the often violent displacement of 700,000 Palestinians, but ignore the fact that more than 60 years have gone by, making it a bit late for a do-over. Ignore the fact that most Israelis weren't even born in 1948, and that Israel is recognized as legitimate by an overwhelming majority of the world's states. Keep insisting on its destruction.
* Use suicide bombings and rocket attacks on civilian targets as a method of warfare. Don't stick to military targets. Instead, blow up civilians on buses and in cafes. Adopting a deliberate policy of war crimes and crimes against humanity helps ensure that few of the world's governments will want to go anywhere near you.
* Get into vicious factional battles with fellow Palestinians. Why present a united front when you can fight with each other? Constant infighting gives the Israelis yet another reason to consider you a worthless interlocutor. And by driving rival party Fatah out of town, you can drive a wedge between Palestinians and give many Arab governments another reason to hope you fail.
* Keep that cycle of violence going! The Israelis killed a Palestinian? Quick, fire a barrage of rockets toward Israel. You know they'll respond with even greater force. Be stubborn and keep up those rocket attacks! Israeli bombs can't tell the difference between your fighters and Gaza's schoolchildren. Let the civilians pay the price for your "brave" resistance.
Israeli style:
* Never pass up a chance to rub salt in open wounds. Keep on building settlements in occupied territory. Stuff like that.
* Undermine and isolate potential interlocutors who might be able to represent the Palestinians. First, destroy Palestinian Authority infrastructure and withhold funds and supplies needed for critical social services, thus helping to push ordinary Palestinians into the arms of Hamas, with its ample social services programs funded by Iran and private Arab donors. Then, when Hamas wins Palestinian elections, isolate Gaza and undermine Hamas.