One thing that I tried and found good, is to pre-generate some d20 rolls. Each player gets their pre-made list and decide what actions to do. Often they'll do multiple attack rolls. They'll just mark rolls off and calculate the result ready to tell the DM. They can also roll damage in the same way, but that matters less.
While it may feel gimiky to let people plan a big attack when they know they'll roll a 20, but let's face it. The team is going to win anyways. This way they'll get to spend it doing something awesome rather than it boosting some melee basic attack.