Manusmriti provides exhaustive details on the modes of Dress,the Staff(Danda) a Brahmin is expected to carry, The process of preparing the Upaveeda How to drink water and how to eat, for Brahmins.
The rules as is the norm are very stringent.
Here they are.
Naming the Brahmin.
31. Let (the first part of) a Brahmana’s name (denote something) auspicious, a Kshatriya’s be connected with power, and a Vaisya’s with wealth, but a Sudra’s (express something) contemptible.
32. (The second part of) a Brahmana’s (name) shall be (a word) implying happiness, of a Kshatriya’s (a word) implying protection, of a Vaisya’s (a term) expressive of thriving, and of a Sudra’s (an expression) denoting service.
33. The names of women should be easy to pronounce, not imply anything dreadful, possess a plain meaning, be pleasing and auspicious, end in long vowels, and contain a word of benediction.
34. In the fourth month the Nishkramana (the first leaving of the house) of the child should be performed, in the sixth month the Annaprasana (first feeding with rice), and optionally (any other) auspicious ceremony required by (the custom of) the family.
35. According to the teaching of the revealed texts, the Kudakarman (tonsure) must be performed, for the sake of spiritual merit, by all twice-born men in the first or third year.
36. In the eighth year after conception, one should perform the initiation (upanayana) of a Brahmana, in the eleventh after conception (that) of a Kshatriya, but in the twelfth that of a Vaisya.
37. (The initiation) of a Brahmana who desires proficiency in sacred learning should take place in the fifth (year after conception), (that) of a Kshatriya who wishes to become powerful in the sixth, (and that) of a Vaisya who longs for (success in his) business in the eighth.
38. The (time for the) Savitri (initiation) of a Brahmana does not pass until the completion of the sixteenth year (after conception), of a Kshatriya until the completion of the twenty-second, and of a Vaisya until the completion of the twenty-fourth.
39. After those (periods men of) these three (castes) who have not received the sacrament at the proper time, become Vratyas (outcasts), excluded from the Savitri (initiation) and despised by the Aryans.
41. Let students, according to the order (of their castes), wear (as upper dresses) the skins of black antelopes, spotted deer, and he-goats, and (lower garments) made of hemp, flax or wool.
42. The girdle of a Brahmana shall consist of a of a triple cord of Munga grass, smooth and soft; (that) of a Kshatriya, of a bowstring, made of Murvafibres; (that) of a Vaisya, of hempen threads.
43. If Munga grass (and so forth) be not procurable, (the girdles) may be made of Kusa, Asmantaka, and Balbaga (fibres), with a single three fold knot, or with three or five (knots according to the custom of the family).
44. The sacrificial string of a Brahmana shall be made of cotton, (shall be) twisted to the right, (and consist) of three threads, that of a Kshatriya of hempen threads, (and) that of a Vaisya of woolen threads.
45. A Brahmana shall (carry), ac cording to the sacred law, a staff of Bilva or Palasa; a Kshatriya, of Vata or Khadira; (and) a Vaisya, of Pilu or Udumbara.
46. The staff of a Brahmana shall be made of such length as to reach the end of his hair; that of a Kshatriya, to reach his forehead; (and) that of a Vaisya, to reach (the tip of his) nose.
47. Let all the staves be straight, without a blemish, handsome to look at, not likely to terrify men, with their bark perfect, unhurt by fire.
48. Having taken a staff according to his choice, having worshipped the sun and walked round the fire, turning his right hand towards it, (the student) should beg alms according to the prescribed rule.
49. An initiated Brahmana should beg, beginning (his request with the word) lady (bhavati); a Kshatriya, placing (the word) lady in the middle, but a Vaisya, placing it at the end (of the formula).
50. Let him first beg food of his mother, or of his sister, or of his own maternal aunt, or of (some other) female who will not disgrace him (by a refusal).
Procuring Food and Eating Procedure.
51. Having collected as much food as is required (from several persons), and having announced it without guile to his teacher, let him eat, turning his face towards the east, and having purified himself by sipping water.
52. (His meal will procure) long life, if he eats facing the east; fame, if he turns to the south; prosperity, if he turns to the west; truthfulness, if he faces the east.
53. Let a twice-born man always eat his food with concentrated mind, after performing an ablution; and after he has eaten, let him duly cleanse himself with water and sprinkle the cavities (of his head).
54. Let him always worship his food, and eat it without contempt; when he sees it, let him rejoice, show a pleased face, and pray that he may always obtain it.
55. Food, that is always worshipped, gives strength and manly vigour; but eaten irreverently, it destroys them both.
56. Let him not give to any man what he leaves, and beware of eating between (the two meal-times); let him not over-eat himself, nor go anywhere without having purified him- self (after his meal).
57. Excessive eating is prejudicial to health, to fame, and to (bliss in) heaven; it prevents (the acquisition of) spiritual merit, and is odious among men; one ought, for these reasons, to avoid it carefully.
58. Let a Brahmana always sip water out of the part of the hand (tirtha) sacred to Brahman, or out of that sacred to Ka (Pragapati), or out of (that) sacred to the gods, never out of that sacred to the manes.
59. They call (the part) at the root of the thumb the tirtha sacred to Brahman, that at the root of the (little) finger (the tirtha) sacred to Ka (Pragapati), (that) at the tips (of the fingers, the tirtha) sacred to the gods, and that below (between the index and the thumb, the tirtha) sacred to the manes.
60. Let him first sip water thrice; next twice wipe his mouth; and, lastly, touch with water the cavities (of the head), (the seat of) the soul and the head.
61. He who knows the sacred law and seeks purity shall always perform the rite of sipping with water neither hot nor frothy, with the (prescribed) tirtha, in a lonely place, and turning to the east or to the north.
62. A Brahmana is purified by water that reaches his heart, a Kshatriya by water reaching his throat, a Vaisya by water taken into his mouth, (and) a Sudra by water touched with the extremity (of his lips).
63. A twice-born man is called upavitin when his right arm is raised (and the sacrificial string or the dress, passed under it, rests on the left shoulder); (when his) left (arm) is raised (and the string, or the dress, passed under it, rests on the right shoulder, he is called) prakinavitin; and nivitin when it hangs down (straight) from the neck.
64. His girdle, the skin (which serves as his upper garment), his staff, his sacrificial thread, (and) his water-pot he must throw into water, when they have been damaged, and take others, reciting sacred formulas.
65. (The ceremony called) Kesanta (clipping the hair) is ordained for a Brahmana in the sixteenth year (from conception); for a Kshatriya, in the twenty-second; and for a Vaisya, two (years) later than that.
66. This whole series (of ceremonies) must be performed for females (also), in order to sanctify the body, at the proper time and in the proper order, but without (the recitation of) sacred texts.
67. The nuptial ceremony is stated to be the Vedic sacrament for women (and to be equal to the initiation), serving the husband (equivalent to) the residence in (the house of the) teacher, and the household duties (the same) as the (daily) worship of the sacred fire.
68. Thus has been described the rule for the initiation of the twice-born, which indicates a (new) birth, and sanctifies; learn (now) to what duties they must afterwards apply themselves.
69. Having performed the (rite of) initiation, the teacher must first instruct the (pupil) in (the rules of) personal purification, of conduct, of the fire-worship, and of the twilight devotions.
70. But (a student) who is about to begin the Study (of the Veda), shall receive instruction, after he has sipped water in accordance with the Institutes (of the sacred law), has made the Brahmangali, (has put on) a clean dress, and has brought his organs under due control.
Manusmrit Chapter 2.31.70