1. Make miswaak at the time of wudhu.
قال أبو هريرة عن النبي صلّى اللّه عليه وسلّم لولا أن أشق على أمّتِي لأَمرتهم بالسواك عند كل وضوء. (بخاري تعليقا 1/259)
Hadhrat Abu Hurayrah (Radhiallahu Anhu) reports that Rasulullah (Sallallahu Alaihi Wasallam) said: Had it not been for the fear of my ummah falling into difficulty (due to not being able to uphold the obligation of miswaak), I would have certainly commanded them to make miswaak at the time of every wudhu.
2. The method of holding the miswaak is that one will place his thumb and small finger under the miswaak, and the remainder fingers will be on the upper-side.
3. One should make miswaak of the teeth horizontally and of the tongue vertically.
عن أبي موسى رضي الله عنه قال دخلت على رسول الله صلى الله عليه وسلم وهو يستاك وهو واضع طرف السواك على لسانه يستن إلى فوق فوصف حماد كأنه يرفع سواكه قال حماد ووصفه لنا غيلان قال كان يستن طولا. (مسند أحمد رقم 19737 )
Hadhrat Abu Musa (Radhiallahu Anhu) reports that I once came to Rasulullah (Sallallahu Alaihi Wasallam) at the time he was making miswaak, and I found him making miswaak of his tongue vertically.
عن عطاء بن أبى رباح رضي الله عنه قال قال رسول الله صلى الله عليه وسلم إذا شربتم فاشربوا مصا وإذا استكتم فاستاكوا عرضا (تلخيص الحبير 1/96)
Hadhrat Ataa ibn Abi Rabaah (Radhiallahu Anhu) reports that Rasulullah (Sallallahu Alaihi Wasallam) said, “When you drink, then drink in sips (i.e. avoid gulping it down), and when you make miswaak, then make miswaak (of the teeth) horizontally.
4. In the absence of a miswaak, one may use his finger as a substitute.
عن أنس رضي الله عنه قال قال رسول الله صلى الله عليه وسلم يجزئ من السواك الأصابع (تلخيص الحبير 1/104)
Hadhrat Anas (Radhiallahu Anhu) reports that Rasulullah (Sallallahu Alaihi Wasallam) said: “The finger can be used as a substitute in the absence of a miswaak.”
5. The miswaak should not be longer than a hand-span, and in thickness it should not be less than the breadth of a finger.