Reading Suah Kahf (Quran Chapter 18) (http://quran.com/18) on Fridays is one of the best deeds you can do, it offers protection from Dajjal. There are many benefits to reciting Surah Kahf on Fridays as mentioned in a previous post.
If you’re seeking an easier way to get protection from Dajjal, you can memorize either the first ten verses or last ten verses of Surah Kahf.
Abu al-Darda (Allah be pleased with him) related that the Prophet of Allah (Allah bless him & give him peace) said, Whoever commits ten verses from the beginning Surat al-Kahf will be protected from the Dajjal. [Muslim, Abu Dawud, Nasa’i, and others; the wording is Muslim’s]
In a narration in Muslim and Abu Dawud it states, From the end of Surat al-Kahf.
Tirmidhi related it with the words, Whoever recites three verses from the beginning of al-Kahf will be protected from the tribulations of the Dajjal. [Mundhiri, al-Targhib wa’l Tarhib, #2172-2173]