"Your sword slashes the target; a clean cut! Blood spills from the wound as the (creature) roars in defiance!"
"The axe comes down with a wicked keening wail! The (creature)'s arm dangles at its side, a bloody wreck!"
"The javelin soars into its target, sinking into the (creature's) shoulder with a thick, meaty thud"
"Your dagger darts forth, a steel snakebite! Your blade gleams with crimson."
"The quiet whisps of arrows thunk noisily into the (creature's) belly, blowing its wind out with a huge whoosh!"
"The crossbow clangs as another quarrel strikes true! A spreading dark stain blemishes the archduke's chest"
"The arsonist has oddly shaped feet"
...and so on.
Best way to go about it is to act it out at the table! Get involved! Show them how the desperate fighter's face looks as he stabs up at the looming troll! Let the determination of the mage shine forth in your eyes as you describe the fury of their burning hands attack!
In short, have fun! :)