Have wudu, wear clean suitable clothing and arrive early for the congregation's announced time.
Anas reports that the Prophet ﷺ ate dates before leaving for the Fitr prayer, in an odd number. Sahih al-Bukhari 953, authentic.
Arrange Zakat al-Fitr before the prayer if it is due from you. Ibn Umar reports the instruction to give it before people went out to pray. Sahih al-Bukhari 1509, authentic. Ask your local mosque about the applicable amount and eligibility; amounts should not be fixed permanently in this guide.
Do not fast on Eid. The prohibition concerning both Eids is reported in Sahih al-Bukhari 1991–1992.