While there are many books about prayer written by saints, they don't all have practical wisdom that can be applied to a lay person.
One of the reasons behind that reality is because most spiritual books are written by religious and for religious.
St. Francis de Sales was unique in writing his Introduction to the Devout Life for lay people.
This means that he recognized the situation of lay people and gave advice that best suited their situation.
Pray in the morning
One of the first pieces of advice he gives is to pray in the morning, rather than at night:
Give an hour every day to meditation before dinner;—if you can, let it be early in the morning, when your mind will be less cumbered, and fresh after the night’s rest. Do not spend more than an hour thus, unless specially advised to do so by your spiritual father.
Pray in a distraction-free zone
He also suggests praying, when possible, in a church or chapel. He explains that it can be difficult to pray at home:
If you can make your meditation quietly in church, it will be well, and no one, father or mother, husband or wife, can object to an hour spent there, and very probably you could not secure a time so free from interruption at home.
Not everyone can pray inside a church every day, but his advice still applies to praying at home, choosing a place that is away from the rest of the family.
Begin prayer with putting yourself in the presence of God
Another piece of advice is to begin prayer by recollecting your spirit and inviting the presence of God:
Begin all prayer, whether mental or vocal, by an act of the Presence of God. If you observe this rule strictly, you will soon see how useful it is.
Worry about the quality, not the quantity
Sometimes we can think that we need to pray many prayers, but St. Francis de Sales suggests we focus instead on the quality:
[N]ot striving to say many words so much as seeking to say a few with your whole heart. One Our Father said devoutly is worth more than many prayers hurried over.
This basic guide can be helpful to many of us, whether we are "veterans" of prayer, or just starting out.