A convention is a technique employed regularly in the drama so that the audience come to attach specific meaning to it. When a technique is used repeatedly in a drama the audience recognise its significance. They buy into it as an established way of telling the story.
There are a range of dramatic conventions that you can explore to make your drama interesting and engage the audience:
slow motion
soliloquy (a solo speech by an actor that gives an insight into what they are thinking)
adding narration
use of an ‘aside’ (when a character directly addresses the audience to comment within a scene)
breaking into song (as in Musical theatre)
using a chorus to comment upon the action
splitting the stage so that different spaces represent different locations
using placards (signs) to give additional information to the audience