I do agree with Rechan's definition of a grind.
On the player's side, there are two things I think you can do to reduce grind.
First, take encounter-defining powers, particularly daily ones, and then actually use them. Certain daily powers are such a big deal that they color everything else that happens that fight. Use them. They tend to be things like Wall of Fire, which can totally reshape the battlefield, or Wrath of the Gods, which can turn a brutal back-and-forth melee into a slaughterfest. With something like Wall of Fire, a fight that might have been boring can become much more interesting, because suddenly powers that push, pull or slide enemies can not only reposition them, but also reposition them into a raging inferno. A power like Wrath of the Gods, by contrast, can increase damage so greatly that a long fight becomes a short one.
Second, take encounter and daily powers that are useful at different points in the arc of a combat. If your attacks in a fight boil down to, "encounter power, encounter power, encounter power, at will, at will, at will, at will, at will," you'll probably feel that a grind occurred. But if your encounter powers are more than "hit for extra damage," if they have tactical relevance and need to be properly timed, you'll probably have something more like "at will, encounter, at will, at will, encounter, at will, encounter, at will." Which will feel like much less of a grind because you spent some rounds not only using an at will power, but also anticipating the use of an encounter power and planning and timing it properly. My fighter uses Bell Ringer, Crushing Blow, and Probing Attack. Bell Ringer is best when used to set up the whole party to beat down a dazed monster, or to grant attack bonuses versus an enemy who can't be flanked at the moment. Crushing Blow is a generic big hit, best used when your attack bonus is at its best, and Probing Attack is best used to set up other attacks. This isn't even a particularly extreme example, but it does show how each encounter power is useful at different moments of the battle.