The Book Of Prayer (Kitaab-ul-Salaat)

The presence of an image (of living objects) in the front, right, left or above the head of
the person offering Prayer.
Offering the bow or prostration, or rising from the prostration before the “ Imaam” does.
Reciting the Qur’ an in any position, except while in Qiyaam (standing).
Ending the Qur’ an recitation in the bowing position.
Resting the hands on the ground before touching the knees while proceeding for
prostration, without a valid reason. Similarly, raising the knees from the ground before
the hands are raised from the ground, while rising from prostration.
Offering Prayer in front of a grave, without a barrier in between.
Not offering a “ Wajib” (Essential act) properly. For example not straightening the back
during the bow and prostrations, or proceeding for the next position before straightening
up in the "Qawmah" or "Jalsah".
Reciting the Qur'an in an improper sequence. For example reciting Surah Kafiroon in the
first “ Rakaat” (Cycle) and Surah Kausar in the second. This is "Makrooh" since it is
against the sequence.
Praying with eyes closed. However, it is better to do so if this increases one's reverence
and devotion.
A “ Makrooh” act makes the Prayer flawed. Such a Prayer should be offered again.
Praying without the head covered is against the Sunnah of the Holy Prophet (peace and blessings
be upon him). Praying without the head covered because one deems wearing a cap as a burden,
or due to heat, is a lesser “ Makrooh” (tanzeehi). However, if it is done in contempt of Prayer
(e.g. deeming that Prayer is not important enough to merit wearing a cap for it), it is Kufr
(blasphemy). If it is done to increase one's reverence and devotion, it is “ Mustahab”
(recommended).
RULES REGARDING CROSSING SOMEONE INVOLVED PRAYER
It is a grave sin to pass in front of someone who is involved in Prayer. The Holy Prophet (peace
and blessings be upon him) said: “ If the one who passes in front of someone involved in Prayer
knew what sin it entails, he would prefer to stand for a hundred years rather than taking that
single step." In another Hadith it is reported "He would deem it good to be driven into the
ground, but would not pass in front of someone involved in Prayer."
If someone passes in front, it does not break the Prayer, but the one who passes will earn a great
sin. Similarly one should avoid praying in a place where it becomes difficult for others who need
to cross.
If a Sutrah (a thing which can act as a barrier) is placed in front of the worshipper, then there is
no harm in crossing from a point beyond it. The barrier should be at least one arm in height and
at least one finger in thickness.