1. When a person wants to travel, and his trip is for a good thing, he should intend to make it sincerely for the sake of Allah, and follow the method and example of the Prophet, may Allah exalt his mention. He should repent from all sins, and should return any valuables he is entrusted with, and pay off his debts, and ask the person with whom he had a problem to forgive him.
2. He should write his will, and have it attested.
3. He should make sure his Hajj provisions are Halal (lawful) so that Allah would accept his Hajj. If one consumes unlawful things his Du’aa (supplication) would not be accepted as reported in the authentic Hadeeth: A person with shaggy and dusty hair would raise his hands to the sky, and ask: ‘My Rubb…My Rubb!’ and his food is Haram, his drink is Haram, his clothes are Haram, and he was fed with Haram…how would he be answered?’
4. The person who wants to travel should look for a good companion who would help him obey Allah.
5. It is praiseworthy to travel on Thursday. It is authentically narrated that the Prophet, may Allah exalt his mention, would travel on Thursday, but if he could not, then he would travel on Monday.
6. It is praiseworthy that the person bid his family, friends, and neighbors’ farewell.
7. It is praiseworthy for the person who wants to travel to say: ‘Bismillah’ i.e. ‘I begin with the name of Allah’, Alhamdulilah i.e. ‘all praise is due to Allah’:
‘Subhanallah aladthee sakhara-lana hadtha wa maa kun’na lawho muq’ri-neen, wa in’na ilaa rab’bina la-munqaliboon.’
He then should say ‘Alhamdulilah’ three times, ‘Allahu-Akbar’ three times, and ‘Subhanakal’laahum’ma in’nee dha’lam’to nafsee fagh’fir-lee in’na-who laa yagh’fe-rodh’dho’nooba il’laa anta.’
After this he should say: ‘Allahumma in’nee us’aluka fi safa-rena hadtha al-birra wat-taqwa wa minnal amali maa tardaa. Allahumma ho-win alaina safarana hadtha wut-we an’na bu’dah. Allahumma antas-Saahibu fis-Safar wul-Khalifato fil Ahal. Allahumma Inni a-oodthu bika min wa’thaa as-safar wa kaa’a’batul mandthar wa so’almonqalab fil maali wal ahl’.
When returning from the trip, one should add after saying the above, ‘Aa’iboon, Taa’iboon, Aa’bidoon, li rabina hamidoon’.
8. It is praiseworthy to travel throughout the night.
9. A person should not travel alone…the Prophet, may Allah exalt his mention, said: ‘The single traveler is a Shaitan, two travelers are two Shaitans, and three are a group.’ (i.e. the person would not transform into a Shaitan, rather, he would be similar to one).
10. Whenever going uphill you should say Takbeer (Allahu Akbar) and whenever going downhill you should make Tasbeeh (Subhanallah).
11. When stopping over somewhere the traveler should say Du’aa of Manzil: ‘A’oodthu bi-kalimaatil’laah-hit-taam’maat min shar’ri maa khalaq’ meaning: ‘I seek refuge with the perfect words of Allah, from the evil of all created things’ The Prophet, may Allah exalt his mention, said that whoever says this would not be harmed by anything until he leaves that area.’
12. It is praiseworthy for the person to supplicate Allah. Abu Hurairah, may Allah be pleased with him, reported that the Messenger of Allah, may Allah exalt his mention, said: ‘Three Du’aa shall be answered without doubt: the Du’aa of the oppressed, the traveler, and the Du’aa of the father (for/against) his son.’
13. It is praiseworthy for the traveler to perform Nafl (supererogatory) prayers while traveling.
From islamhouse.com