In NSW, a by-law requires approval by 75 per cent of the unit entitlements of owners voting in person, by proxy or by other valid means. NB: Not all owners – just those voting.
Your agenda should note which motions will require a special resolution, and special resolutions must be calculated by unit entitlements.
By the way, any owner can ask for any motion to be calculated by a “poll” vote (unit entitlements), during the discussion or immediately after a show of hands.
Other states have different methods of calculating special resolutions and different criteria for passing by-laws..