Maintain focus during prayer

In Colossians 4:2 (NLT), Paul says,

Devote yourselves to prayer with an alert mind and a thankful heart.

And in Ephesians 6:18 (NLT), Paul says,

Stay alert and be persistent in your prayers.

Proper prayer is hard work! These verses, and many others like them, command us not to be casual and lazy about prayer. But how do we maintain focus during prayer? Today, let us follow the advice given by Jesus in Matthew 6:6 (NLT),

When you pray, go away by yourself, shut the door behind you, and pray to your Father in private.