Rolling with It
Some DMs rely on die rolls for almost everything, Whe a character attempts a task, the DM calls for a check an picks a DC* As a DM using this style, you can't rely on the characters succeeding or failing on any one check to move the action in a specific direction* You must be ready to improvise and react to a changing situation.
Relying on dice also gives the players the sense that anything is possible. Sure, it might seem unlikely that the party's halting can leap on the ogre's back* pull a sack over its head, and then dive to safety, but with a lucky enough roll it just might work.
A drawback of this approach is that roleplaying can diminish if players feel that their die rolls, rather than their decisions and characterizations* always determine success.