Among the brakhot most of us know by heart is the one recited before eating bread: hamotzi lechem min ha'aretz. It acknowledges God for being the One "who brings forth bread from the earth." This brief acknowledgment of the connection between the physical and spiritual worlds is an expression of that basic value of our tradition and its world view.
There is a familiar kavvanah attached to this blessing, though you probabably consider it a children's song. "We give thanks to God for bread; our voices rise in song together as our joyful prayer is said." The enhancements of the mitzvah of reciting this blessing are clear: giving thanks, singing, acting as a community, being joyful.
Unless you have small children at your table, you are probably not going to hear this little ditty with its innocently powerful message. How could you enhance the act of eating with a moment of reflection before or after reciting hamotzi?
One way is to compose your own brief reflection. All sorts of expressions of intent are apropriate. You may wish to remember the bounty which is yours and pledge not to ignore those who go hungry. You may wish to acknowledge the complicated interdependence of animal, vegetable and mineral which resulted in this bread -- and our obligation to preserve it. You may wish to reflect on the act of reciting hamotzi as a link with Jews throughout the ages and throughout the world. You may wish to look for God's handiwork in a humble piece of bread, and pray for the insight to see that handiwork in God's human creations.
A wonderful Sephardic custom involves sprinkling the bread with salt before the first bite (a remembrance of the sacrifices and act of hospitality) and reciting adonai melekh, adonai malakh, adonai yimlokh l'olam va'ed (God rules, has ruled and will always rule). The wordplay in the phrase is a pun: melach (with a chet at the end) means "salt;" melekh (with a khaf) means "rules."
I would commend to you a wordless kavvanah. Though we are to follow the recitation of a brakha immediately with the act it sanctifies. I would urge you to hesitate between the end of the blessing and your first bite. In an age in which immediate gratification is the rule of the day, a symbolic pause between saying and doing can make an important statement. And if we can learn to reflect for a moment before putting something into our mouths, maybe we will learn to do the same for that which comes out of our mouths.