Proper clothing: What is implied?
One should adjust his clothing and make himself neat and presentable before [praying], as [implied by Psalms 29:2]: "They bow to God in resplendent holiness."
One should not pray wearing [only] his undershirt, bareheaded, or barefoot - if it is the custom of the people of that place to stand before their most respected people with shoes.
In all places, one should not hold tefillin in his hand or a Sefer Torah in his arms during the Amidah, since he will worry about them. [Similarly,] one should not hold utensils or money in his hand. However, he may pray while holding his lulav on Sukkot, since it is the commandment of the day.
If one is carrying a burden of less than four kabbim on his head when the time for the Amidah arrives, he should throw it over his shoulder and pray. If it is larger than four kabbim, he should place it on the ground and then pray.
It is customary for all Sages and their students to pray only when wrapped in a tallit.