# Let the word of Christ live in you richly

"Be obedient to the instructions of Christ" or "Always trust Christ's promises" 

# singing psalms and hymns and spiritual songs

"singing all sorts of songs to praise God." 

# psalms

These are probably songs from the Old Testament book of Psalms that Christians sang.

# with thankfulness in your hearts

"with thankfulness in your minds" or "being thankful"