Besides the devotion to the Most Holy Rosary of the Blessed Virgin Mary, those that proclaim the One, Holy, Catholic, and Apostolic faith utilize an age old spiritual practice called a novena.

A novena is a nine day prayer dedicated for intercessory needs by which may
be piously request through those in Heaven including Our Lord Jesus.
Now of course, a novena dedicated to our Lord differs from that of
ordinary intercession through the saints as Jesus is
to be given adoration and worship only.
 

We find, however, asking particular saints such as Mary, Queen of Heaven and earth, to also be of particular difference as she was and is said to be the
Co-Mediatrix of our salvation (which has not yet been made doctrine).

What that means is that Our Lady is of significant elevation in
holiness as she was purposed to laboralongside Christ for the salvation of souls.

Though she is not God nor equal to Him, God did include Our Lady
to correspond her sufferings with that of Jesus’ Passion
and death for the benefit of all who would have recourse to her and her Son.

Knowing this, we also recognize the great importance of devot 
persistence in prayer for the desire to obtain signal graces from God.

This is why the novena is an incredible and powerful prayer and spiritual exercise.
According to the Catholic Encyclopedia,

“a novena is a nine days’ private or public devotion in the Catholic Church
to obtain special graces…to the novena belongs that hopeful mourning,
of yearning, of prayer.

The number nine in Holy Writ is indicative of suffering and grief”
(St. Jerome, inEzech., vii, 24; — P.L., XXV, 238, cf. XXV, 1473)”

So understanding that a novena is a prayer of fasting and of mourning
for intercession over a period of nine days, one can begin to see
the spiritual benefit of this practice come to light.

Keep in mind, any holy soul, not just Jesus and Mary,
whether in Purgatory or in Heaven may be fit to dedicate a novena to,
for the purpose of sanctification and fulfillment of a worthy petition.

What constitutes a “worthy petition”?
A worthy petition is a request for something that results in according
to God’s will, such as, requesting graces to avoid sin,
or for the conversion of sinners, etc.

But above all, the greatest among all novenas are those that are dedicated to the
Sacred Heart of Jesus and the Immaculate Heart of Mary.

In your nine days of petition, make sure to focus on specific meditations
listed for these devotions and be sure to rid yourself of all distractions
and focus deeply on the words you are praying as though you were
reciting them out of a profound love found only in a marriage vow.

Reverently consider who it is that you are speaking with
and lend all your attention so as to be respectful.

Remember, the more you put into it the more you get out of it.
The greater the love and faith the greater reward. And always remember,

7:7  Ask, and it shall be given you: seek, and you shall find: knock, and it shall be opened to you.
7:8  For every one that asketh, receiveth: and he that seeketh, findeth: and to him that knocketh, it shall be opened. – Matthew 7:7-8