Adding Flair With Threes - Under the Bridge
Often, drum grooves involve straight 8th notes played on the hi hat or cymbal. That's not necessarily a bad thing, as long as it's what the music calls for. However, there are many opportunities where adding an additional stroke in-between the 8th notes will improve the song.
Remember that the most important part of being a drummer is playing for the music. Don't add things to a beat just because you can. Make sure it serves the music.