1. When ever you leave a house, put your left foot out first.
2. When leaving home for the Masjid or for any other place, recite this Dua: (Tirmidhi, Abu Dawood, Ibne Maajah)
Trans: I emerge with the name of Allah. I have placed my trust in Allah. The strength to abstain from sins and to carry out righteous deeds, is only from Allah (Shami , Vol.1 pg. 85)
[It is stated in the hadith that if a person recites the above dua and departs then there is an (unseen) procalamation that his need will be fullfilled and that he will be protected from any harm or injury. On hearing this dua, the Satan goes away from the place and refrains from troubling the reciting person. (Tirmidhi)]
Also resite:
اللَّهُمَّ إِنِّي أَعُوذُ بِكَ أَنْ أَضِلَّ أَوْ أُضَّلَّ أَوْ أَظْلِمَ أَوْ أُظْلَمَ أَوْ أَجْهَلَ أَوْ يُجْهَلَ عَلَىَّ
Trans: "O ALLAH, I seek refuge in You from misleading or being misled or oppressing or being oppressed or from being ignorant or bearing the result of ignorance". (Mishkat)
3. Mohammad (PBUH) Always opened door with Bismillah before leaving house.(Abu Dawood)
4. Proceed with dignity. Do not run. (This pertains to going to the Masjid only). (Ibne Majah)