First of all, Islam depends heavily on the word: 
"Allah." 
Because Islam is the complete submission and obedience to Allah (God).
The name Allah (God) in Islam never refers to Muhammad (pbuh) or to anyone or anything else which Allah has created, as many Christians may think; Allah is the personal name of God.

What do Muslims believe about Allah?

1. He is the one God, Who has no partner.
2. Nothing is like Him. He is the Creator, not created, nor a part of His creation.
3. He is All-Powerful, absolutely Just.
4. There is no other entity in the entire universe worthy of worship besides Him.
5. He is First, Last, and Everlasting; He was when nothing was, and will be when nothing else remains.
6. He is the All-Knowing, and All-Merciful, the Supreme, the Sovereign.
7. It is only He Who is capable of granting life to anything.
8. He sent His Messengers (peace be upon them) to guide all of mankind.
9. He sent Muhammad (pbuh) as the last Prophet and Messenger for all mankind.
10. His book is the Holy Qur'an, the only authentic revealed book in the world that has been kept without change.
11. Allah knows what is in our hearts.

These are some of the basic guidelines Muslims follow in their knowledge of God:

1. Eliminate any anthropomorphism (human qualities) from their conception of Allah. His attributes are not like human attributes, despite similar labels or appellations.

2. Have unwavering faith in exactly what Allah and Prophet Muhammad (pbuh) described Allah to be, no more, no less.

3. Eradicate any hope or desire of learning or knowing the modality of His names and attributes.

4. Belief totally in all the names and attributes of Allah; one cannot believe in some and disbelieve the others.

5. One cannot accept the names of Allah without their associated attributes, i.e. one cannot say He is Al-Hayy - 'The Living' and then say that He is without life.

6. Similarity in names (or meanings) does not imply similarity in what is being described (referents). As a robotic arm differs from a human arm, so the "hand" of Allah is nothing like a human hand, His speech is nothing like human speech, etc.

7. Certain words are ambiguous or vague in their meanings, and thus may be susceptible to misinterpretation. Only those meanings that are in accordance with what is specified by Allah and His Prophet (pbuh) are acceptable.