Time is a musical constant-- turn on a metronome and its there. Groove evolves with each musician contributing their feel to the brew. The Count Basie rhythm section of the 30's and 40's set the standard. No matter what style of music you play, these guys (Count Basie, Jo Jones, Walter Page and Freddie Greene) were it!
Give and take is another aspect of groove playing. Killer Joe from Quincy Jones' "Walking in Space" is a wonderful example of this.
Killer Joe is also an example of hearing and awareness. You can't play a groove without being aware of the length of the beat. You develop this awareness by listening.
Groove more than anything is a state of mind, If you hear it you will achieve it.
the groove continues...