The worshipper must be humble in his prayer, and should avoid everything that may distract him from it, such as adornments and decorations. He should try
to avoid praying where there is food that he wants to eat, or when he needs to urinate or defecate, as this will take away humility and concentration from the prayer.

'Aa'ishah (may Allah be pleased with her) said that she heard the Messenger of Allah (may the peace and blessings of Allah be upon him) saying,

"No prayer should be performed when food has been served, nor should it be performed when a person is in need of relieving himself." [Muslim: 560]

Whilst standing in prayer, you should focus your sight to the front.  You should avoid looking around to the left and right, or up at the sky, as the Prophet (may the peace and blessings of Allah be upon him) said:

"Why are some people looking towards the sky during the prayer?" His talk grew stern while delivering this speech and he said, "They should stop (looking towards the sky during the prayer); otherwise their eye-sight would be taken away from them." [al-Bukharī: 750; Muslim:429]

 The Prophet (may the peace and blessings of Allah be upon him) forbade three things:

"Pecking [in prostration] like a hen, lying [in prostration] like a dog, and looking around like a fox." [Ahmed: 8106]

They should avoid being distracted by images or patterns on prayer mats or clothing, as this was the way of the messenger of Allah (may the peace and blessings of Allah be upon him) as in the following narration by 'Aa'ishah (may Allah be pleased with her) who said:

"The Prophet (may the peace and blessings of Allah be upon him) prayed on a garment with marks on it. During the prayer, he looked at its marks. So when he finished the prayer he said, 'Take this garment of mine to Abu Jahm and get me his inbijaniya [a woolen garment without marks], as it has diverted my attention from the prayer." [Bukhari: 373]