Muslims make an intention to fast; one that must be made the night before. There are no known (valid) narration of the Prophet (SAW) actually uttering any intention aloud. Such intentions need not be said out loud, it is but as silent note of intent one makes within.

The Prophet Muhammed (SAW) said: "Whoever does not determine to fast before dawn, his fast is null and void." - Ahmad

The length of the fast is from dawn to sunset. This could range from between 10 hours to as much as 20 hours in certain places. Before dawn, one has to take his Suhoor and abstain from everything that would invalidate the fast until sunset.

The Messenger of Allah (SAW) told us: “Eat Suhoor for in Suhoor there is blessing.” - Muslim

“Verily that which separates between our fast and the fasting of the People of the Book is the Suhoor.” - Muslim

Suhoor should not be skipped even though there is no sin in this, but it leads to missing out on the blessings of it as stated in the above narrations. It also brings strength which will be needed as the day goes on. The Prophet (SAW) used to delay his suhoor until just before dawn.

Solat to a casual observer seems a complex and demanding task but it is important to a muslim. There is no fast without Solat. In fact, without solat, you can barely pass as a Muslim. But the institution of prayer in Islam is a well developed one, where the individual is required to pray 5 times a day, alone or in a congregation with others. Missing out on Solat during the fast will be a huge loss as the difference between a believer and a disbeliever is the prayer.

If one accidentally swallows food, maybe while cooking or simply a random act of sincere forgetfulness then his fast is still valid.

The Prophet (SAW) said: “Whoever forgets he is fasting and eats or drinks something should complete his fast, for it is merely that Allah has given him food and drink.” - Muslim

It is worth knowing that it is considered haram to use your fast as an excuse to remain unproductive during the day, that could be at work, at home or school. We refrain from vain talk, non beneficial discussions, fights and arguments. We should seek to help those around us and double our good deeds.

Fasting is a shield; so when one of you is fasting he should neither indulge in obscene language nor should he raise his voice in anger. If someone attacks him or insults him, let him say: "I am fasting!" - Muslim

Hastening to break the fast immediately after sunset is sunnah. This was done to prevent a repeat of a common practice of the people of the book who waited well into dusk before breaking their fast.

The Messenger of Allah (SAW) said: "People will continue to adhere good along as they hasten to break the fast." - Buhkari and Muslim

The Prophet (SAW) would break his fast before offering Magrib with three dates or three draughts of water if there was no date available. (Abu Dawood). This is a far cry from the way we break our fast today with iftaar looking more like a feast.

We controlled our urge all day and abstained from all that has been restricted to us, all  to attain the pleasure of our Rabb. Hence, we make dua at the time of breaking our fast.

Prophet Muhammed (SAW) said: "The supplication of a fasting person upon breaking his fast, will not be rejected." - Ibn Majah

There are well known dua related to the above hadith:

"The thirst is gone, and the veins replenished and the reward us confirmed, if Allah wills" - Abu Dawood

"O Allah! For you I have fasted and in You i have believed and upon You I have relied, and with Your provisions I break my fast."