What are some of the other basics of becoming a Muslim?

[فداء الرسول]

Allah’s Messengers


Belief in the prophets, prayers and salutations of Allah be upon them.
Belief in the process of prophethood.
Allah in His wisdom did not neglect His creation.
Prophets sent to guide us in this life and the next.
Specific belief in the 25 prophets named in the Qur'an: (1) Adam, (2) Nuh, (3) Idris, (4) Saleh, (5) Ibrahim, (6) Hud, (7) Lut, (8) Yunus, (9) Isma'il, (10) Is-haq, (11) Ya'qub, (12) Yusuf, (13) Ayub, (14) Shu'aib, (15) Musa, (16) Harun, (17) Alyas', (18) Dhu Al-Kifl, (19) Daud, (20) Zakariya, (21) Sulaiman, (22) Ilyas, (23) Yahya, (24) Isa, and (25) Muhammad, prayers and salutations of Allah be upon him and upon all the messengers of Allah.
General belief that there are many other prophets and messengers, but never assuming anything without knowledge from Allah (i.e. Qur'an and Sunnah).
The subject matter of the prophethood.
Warnings and glad tidings.
So the disobedient will have no excuse before Allah. (Prophets sent to every nation.)
Enjoining the worship of Allah and the avoidance of At-Taghoot (Shaitaan, etc.) [Study: 4/165, An-Nisaa; 16/36, An-Nahl]
Attributes of the Prophet Muhammad:
Seal of the prophets; Imam of the pious; Foremost among the sons of Adam; Imam and Khatib of the prophets when they assembled; Possessor of the Praiseworthy Position which all of mankind will wish they had attained (and which is mentioned in the Du'a of hearing the adhan); Owner of the pool in paradise; Intercessor for all mankind on the day of Qiyama (Judgement Day).
Allah sent him with the best of the books and the best of His law. Allah made his nation "the best nation brought forth for mankind." Allah gave him (and us) all of the good that was given only partially to the previous nations. His nation is the last in creation, the first in resurrection.
From the moment of his prophethood, Allah made him the criterion (Al-Farooq) for distinguishing Allah's allies and their actions from His enemies and their actions: None can have any relationship to Allah except through belief in the Prophet (sas) and following what he brought in public and in secret. Whoever claims love or closeness to Allah while disobeying the message is actually drawing closer to Shaitaan, farther from Allah.


Allah’s revealed Books


Muslims should have general belief in the phenomenon of the sending of the revealed books. Keep in mind, all the revealed books were allowed by Allah to be corrupted, except the Qur'an.
Six specific books mentioned in the Qur'an:
As-Suhuf of Ibrahim (Abraham) and Musa (Moses).
Az-Zaboor given to Daud (David).
At-Taurat (The Torah) revealed to Musa.
Al-Injeel revealed to Isa (Jesus).
Al-Qur'an - the final revelation.


Attributes of the Qur'an:
Flawless and untampered with: [See 41/42 Fusilat]
The final authority over any remnants of the previous books. [See 5/48 Al-Maidah]
A guidance and a mercy. [See 10/37 Yunus]
The Qur'an must be followed and applied. [See 6/155 Al-An'aam]

Source: http://muttaqun.com/shahada.html