Pray first thing in the morning...before my time seems to slip away with the busyness of the day.
Pray for lunch...nice little respite to break up the work day and be strengthened in the Lord.
Pray before bed...wonderful way to end the day, thanking God for what He has done, asking forgiveness for any sins committed, asking protection throughout the night.
As far as how much...not enough. Especially as i read some of the early Puritan practices of prayer.