Sukracharya(Venus in astrology) said "The first pada is  and means - we worship or sing the praise of Lord Trayambaka. 'Tryambaka' is the name of Lord Shiva as the father of the three worlds - bhu, bhuva and svarga lokas. He is the father and lord of the three mandala's - Surya, Soma and Agni mandala. He is Maheswara, the lord of the three Guna's - Satva, Rajas and Tamas. He is the Sadashiva, the teacher of the three tatvas - Atma tatva, Vidya tatva and Shiva tatva. He is the father (cause and source) of the three energies (agni) - Aavahaniya, Garhapatya and Dakshinagni. He is the father of all physical creation through the three murti bhuta - Prithvi (solid), Jala (liquid) and Tejas or agni (energy). He is the lord of the three heavens created by the dominance of the three Gunas - Rajas (Brahma), Satva (Vishnu) and Tamas (Shiva). Know Him to be the nirakara (formless) Sadashiva as He is above this physical mode and is their Maheswara. This is the first foot of the mantra (composed of eight syllables)."

"The second pada of the mantra," continued Sukracharya, "is . 'Sugandhim' refers to the fragrance of the flower that spreads in all directions, and in a similar way Shiva is present in the entire creation, both animate and inanimate. In all the bhutas (modes of existence), in the three Gunas (nature of creation as being Satva, Rajas or Tamas), in the ten indriyas (five gyana-indriyas or senses and five karma-indriyas or organs of action), in all the devas (33 devas are the source of all illumination and enlightenment) and the ganas (hosts of demi-gods), Shiva exists and pervades as the illumine atma (soul) and is their essence. 'Pustivardhanam' is now being explained. That inward dwelling spirit (atman), the Purusha Shiva is the real sustainer of Prakriti (and not vice-versa as all people perceive). Starting with the mahatatva (primordial state of matter/energy) to the individual parts of creation, the entire sustenance of the physically created beings (both animate and inanimate) is done by the imperishable Purusha. You, I, Brahma, Vishnu, the Munis and even Indra & devas are maintained/sustained (by the atma and that is Him). Since the Purusha (atma - Shiva) is the granter of sustenance to prakriti (body/nature), he is 'Pusti-vardhana'."

Having explained the first two pada of the mantra, Sukracharya continued to explain the remaining two pada. He said " the next two pada (consisting of sixteen syllables) is  meaning - Prabhu! just as the ripe cucumber is severed from the bondage of the creeper, in the same manner may we be delivered from death for the sake of immortality (moksha). Rudra deva is like amrita (nectar of immortality). Those who worship Him with good karma, penance and repentance, meditation, contemplation, prayer or praise, will surely renewed life and vigor. The strength of truth force (in this mantra) is such that Lord Shiva shall definitely free the worshipper from the bondage of death because Shiva alone is the giver of bondage and moksha.

Here is a shloka you can say last thing at night.

This is the meaning :

Whatever I have done with my hands or feet, or speech, my body or my actions, 
Whatever I have heard or seen, or thought, all my mistakes, 
Whether knowingly or unknowingly, please forgive them all, 
Great all forgiving God, Mahadeva Shambhu.

The shloka :

Kara charana krutam vaak kaayajam karmajam vaa

shravan naya najam vaa maanasam vaaparaadham

vihita maavihitam vaa sarvametat shamasva

jai jai karunabdhe shri maha deva shambho.