It's a comprehensive list of good ideas, several of which I am taking and more of which I'd like to take. Please run down it and pick some that you can do as there is something for everyone here ranging from writing a letter to the editor to learning Arabic.
1) Educate yourself via reliable books. For example books by Ilan Pappe (Ethnic Ceansing of Palestine), Edward Said (The Question of Palestine).
2) Educate yourself and track current information and key historical data via websites (and disseminate it). For example look into http://www.imemc.org/, http://electronicintifada.net/, http://english.aljazeera.net/, Encyclopedia of the Palestine Problem, Palestine Remembered, and similar websites.
3) Educate yourself by visiting Palestine and writing about it. There are many organizations doing tours that inspire. Examples Siraj Center, Alternative Tourism Group, Holy Land Trust, Global Exchange, Birthright Unplugged, ISM etc
4) Practice using clear and unambiguous vocabulary including language to protest apartheid and colonization. See for example developing anti-partheid framework for the struggle (PDF File): http://www.endtheoccupation.org/downloads/AAF%20curriculum%20training%20.pdf
5) Challenge media bias by first educating yourself and others about its existence and the extent of the bias. See for example http://ifamericansknew.org/
6) Write to the mainstream media. You can do letters to the editor (usually 200 words) and/or opinion pieces (700-900 words).
7) Start your own group or join an existing organization that works for justice. Simply search/google your city with the word Palestine to identify candidates.
8) Join the International Solidarity Movement, the Ecumenical Accompaniment Program (EAPPI), Christian Peace Maker Team or other groups doing work in the occupied areas
9) Develop close working relationship with progressive parties and groups in your country.
10) Network and enhance groups working on sanctions and suspension of US aid to Israel. e.g. Suspend US Aid to Israel Now
11) Lobby. This is done individually or by supporting/joining one or more od the many groups doing it, e.g. Council for the National Interest, Citizens For Fair Legislation, American Arab Anti-Discrimination Committee, Center for Policy Analysis on Palestine, and American Association for Palestinian Equal Rights (http://www.aaper.org/).
12) Hold a teach-in, seminar, or public dialogue. This is straightforward: you need to decide venue, speakers, and do publicity. This can be facilitated through such groups as Palestine Media Watch which have speakers bureaus.
13) Send direct aid and support for people on the ground through transparent and trustworthy groups.
14) Use youtube and googlevideo to disseminate information
15) Challenge Israel in local and International courts.If you are a lawyer, donate your time and start some networking and initiate cases (e.g. US congress is violating US laws by sending money to Israel, US Citizens can bring cases against foreign governments that harmed them). Groups with great interest and activism on behalf of Palestinians includes Lawyers Without Border, National Lawyers Guild, Al-Haq, Yesh Din, and Adalah - Legal Centre for Arab Minority Rights in Israel.
16) Help coalitions work for Palestine and insist they do not leave this issue; example is http://CTUnitedforPeace.org.
17) If you work in a group, suggest formation of local or national coalitions to increase the power by association.
18) Join the campaigns for economic boycotts. For example see successful examples here: http://www.qumsiyeh.org/boycottsanddivestment/
19) Join or initiate a campaign for cultural and academic boycott; see also http://pacbi.org/.
20) Host an art exhibit or other art performance (music, dabka etc) that highlight the rich Palestinian culture.
21) Engage in civil disobedience actions to draw attention and change policies.
22) Develop campaigns to support the right to enter: see www.righttoenter.ps
Israel Takes Aim At Palestinian Families By Ida Audeh
23) Facilitate a visit by the Wheels of Justice bus tour to your area (in the US) or create a bus like that (e.g. in Europe). See justicewheels.org
24) Donate to aid Palestinian Children. For example, Palestine Children Relief Fund, and Playgrounds for Palestine
25) Develop campaigns to ban Political Junkets to Israel.
Here is an example "In a challenge to one of the most powerful lobbying tactics used by the Jewish community, a county in Maryland decided last week that local legislators could no longer go on sponsored trips to Israel. http://www.forward.com/articles/11553/
26) Support the campaigns to end the siege on Gaza. See http://www.freegaza.org/, http://www.witnessgaza.com/
27) Work in your country against discrimination
Arabs Against Discrimination: http://www.aad-online.org/
American Arabs Anti-Discrimination Committee http://
28) Support Human Rights: Amnesty International http://www.amnesty.org, Human Rights Watch: http://hrw.org/doc/?t=mideast&c=isrlpa
B’Tselem:The Israeli Information Center for Human Rights in the Occupied Territories http://www.btselem.org
29) Support the Right to Education Campaign: http://right2edu.birzeit.edu/
30) Donate to United Nations Relief and Works Agency: http://www.un.org/unrwa/
31) Work against home demolistions:
Israeli Committee Against House Demolitions: http://www.icahd.org/eng
32) Support empowering Youth from Palestine e.g. see http://www.yfppal.com/ and http://www.alrowwad-acts.ps
33) Write to and work with alternative mass media (like DemocracyNow, Public Access TV).
34) Create your own content and post it to the web
35) Utilize social networking sites to reach a mass audience (e.g. facebook,
36) Go into chat rooms, email discussions etc and spread the word.
37) Buy Palestinian Products, for example from www.palestineonlinestore.com, www.canaanfairtrade.com, www.palestinefairtrade.org.
38) Pray for Peace and Justice or if you are not religious, take time out to think and meditate on what can be done to achieve Peace with Justice
39) Make a podcast or public service announcement and spread it
40) Drop a banner from a traffic bridge or any other publicly visible location
41) Put out an information table in a university student center, public gathering, festivals, or other places where people congregate.
42) Host a fundraising party or dinner at your home.
43) Show a documentary in a public setting and then have a discussion about it.
44) Organize a public debate between those who support Zionism and those who support equality and justice
45) Learn Arabic or if you are an Arab learn another language (including Hebrew) so that you can communicate better
46) Make a street theater
45) Engage in Civil disobedience acts (this may entail getting arrested).
46) Reach out to Christian religious leaders and ask them to act based on the Kairos Palestine document www.kairospalestine.ps
47) Challenge the Zionist attempts to doctor Wikipedia (ie. imposing a Zionist distorted version on this free web encyclopedia).
48) Start a genuine interfaith dialogue based on acting for justice rather than chatting to hide injustice.
49) Find a way not to pay taxes to governments that violate human rights and use your taxes for war and oppression.
50) Host a dinner with Arabic food and show people the rich cultural traditions like embroidered dresses that go back to Canaanitic times.