(1) Start by joining your Democrats Abroad Committee at http://www.democratsabroad.org and ask for for help in absentee registration and voting, or go directly to http://www.votefromabroad.org/ and complete the absentee ballot request form, no later than September 15th.
(2) Also, visit the Federal Voting Assistance Program’s website at http://www.fvap.gov/... for more information on the absentee registration and voting process in your state.
read the rest of the 9 below.
(3) Ensure that you have applied for your absentee ballot using the hard copy or on-line versions of the FPCA available at: http://www.votefromabroad.org/
(4) Make sure your U.S. local election official has your current mailing address.
(5) Sign and date all election materials.
(6) Fulfill your state’s witness/notary requirements (if required).
(7) Ensure that your ballot or FPCA is postmarked.
(8) Register to vote and request your ballot in a timely manner - not later than September 15th.
(9) VOTE - mail your ballot not later than October 10th of the election year.
And for Bonus Points-- help get the above info our to every American you meet in the next 4 1/2 months!
(h/t to DA Guatemala for this useful list)