Goddess Parvati

Goddess Parvati is also known as Goddess Durga,Her consort is Lord Shiva who Mediates in Himalayas.She is also called by Goddess Lilita.She also exists in Various forms,both friendly and fearfull forms.Two of her very powerfull forms are
1.Durga Devi - Who is mainly worshipped by married women for a happy married life.
2.Goddess Kali - She is the Goddess of Destruction.

Both of these two forms have eight heads and great power and energy(Shakti).Goddess Durga rides on a lion and Goddess kali rides on a corpse of a demon.As Goddess Kali is the destruction form,She has the garland of skull,blood etc.

Goddess Durga is also known as the Mother of the Universe,She is belived to be the power behind the creation,preservation and destruction of this world

Goddess Kali love her devotees inspite of her fearful appearance.In this relationship the devotees (or) worshippers becomes a child and Kali takes the form of the ever caring Mother.She was born from the brow of Goddess Durga,during one of her battels with the evil forces.Goddess Parvati was also called sati in her previous divine incarnation.

Mantra-
"Om Sri Durgaya Namaha"
Meaning -
This Mantra is the powers of Goddess Lakshmi ,Goddess Saraswati and Goddess Kali.By spelling this Mantra one's a day ,A persons physical,Mental and economic problems will be solved.
Chanting Durga Mantra once in a day  will help you in help you in getting good wealth and prosperity.

Goddess Laxmi or Goddess Of Wealth

She is the Goddess of wealth and prosperity.She is the wife of Lord Vishnu.Goddess Lakshmi is mostly worshipped by Hindu families , even though she is worshipped daily,the month october is the festive month for Goddess Lakshmi.Lakshmi puja is celebrated on the full moon night of Kojagari purnima.

She is belived to have come out from the froth of the Milk ocean when it was churned by devas and Asuras,with full beautiful lotus in her hand.Goddess Lakshmi represents a beautiful woman with golden complexion,with four hands sitting (or) standing on a fully bloomed lotus and holding a lotus bud,This refers the beauty,purity and fertility.

When ever Lord Vishnu takes a different Avatar,she appears as divine,even when he becomes mortal,she also does,transforming her own person to what ever Avatar Lord Vishnu takes.Gold coins are seen flowing from her hands, which suggest that those who worship her will gain wealth.

Mantra -
"Om Sri Maha Lakshmi Namaha"
Meaning -
This Mantra will help in getting all the fortune and wealth that we are about to get.MahaLakshmi stotram will also give power to gain more wealth and prosperity.

Goddess Saraswati or Saraswati Goddess

Goddess saraswathi is the Goddess of Music,Knowledge and all the creation arts.She displays the power of speech and learning.She is the consort of Lord Brahma.She is shown in a white saree which is a sign of purity and rides a swan and sometimes a peacock holding veena in her hands.Playing veena indicates the Love towards Music.She also holds a Mala and a palm leaf scroll which indicates Knowledge.Many students all over the world worship Goddess Saraswathi to perform well in the examinations.A temple named vilma vashi in Diwara is built to Goddess Saraswati.

The Below sloka (Mantra) of Goddess saraswati can be read daily to improve Memory power and concentration in studies.

Mantra -
"Om Aim Saraswatyai Namaha"

Repeating Saraswathi Mantra per day , A person can improve Knowledge ,Memory and the power of speech.

Lord Krishna or Lord Radha Krishna

Lord Sri Krishna is the eighth incarnation (Avatar) of Lord Vishnu,when mother earth was unable to bear the sins and burden committed by the evil kings and rulers.Then Lord Brahma,the creator appealed Lord Vishnu to help .Lord Vishnu assured him that he would soon be born on earth to eliminate all the evil forces.

Lord sri Krishna was the eighth child of Devaki and Vasudeva in a prison cell.He was then grown in Gokula by Vasudeva friend Nanda and yashoda.After he grown up he Killed the evil King Kamsa and freed his parents Devaki and Vasudeva from the prison and became King and ruled Mathura city.

In Mahabharata Lord Sri Krishna played a major role in the victory of Pandavas against kauravas.During the war against kauravas Lord Sri Krishna delivers Bhagavad Gita(The song of the celestial one),which inspires Arjuna and think that it was right to fight against his kinsmen since they were unrighteous.

Lord Srikrishna also stated that yoga and devotion that will lead to oneness with God.

Mantra -
Hare Krishna Hare Krishna
Krishna Krishna hare hare
Hare rama hare rama
rama rama hare hare

Chant when in trouble and the lord is with you to solve all your sorrows and obstacles on your way.
You can also chant Lord Krishna Mantras , Damodarastakam , Madhurashtakam , so as to please lord to turn away all the difficulties  from you and lead a peacefull life.