God cannot fill what has not been emptied...

Benedict gives us a great prayer for the day:

Almighty God, give us wisdom to perceive you,
intelligence to understand you,
diligence to seek you,
patience to wait for you,
vision to behold you,
a heart to meditate upon you,
a life to proclaim you;
through Jesus Christ our Lord,
who lives with you now and the Holy Spirit,
one God now and for ever.

For those who struggle with the mechanics, practise, and sense of prayer, from George MacDonald:

"He that prays and does not faint will come to recognize that to talk to God is more than to have all prayers granted - that is the end of prayer.