Depending on what state you are in, there might be differences in what can be approved and by what mechanism. EG. in the ACT the Act says the EC can pass a resolution to approve ‘minor’ alterations to the common property such as an awning if it would not interfere unreasonably with the reasonable use and enjoyment of the common property by other owners. The Act gives an awning or an airconditioner as examples of minor incursions on the common property but what is minor in one OC could be major somewhere else depending on the layout of the common property. An general meeting could pass a resolution to direct the EC to only approve certain sorts of awnings, for example. On the other hand, in the ACT, an unopposed resolution is required to grant a ‘special privilege’ to use common property. Permission to have exclusive use of a particular parking space would generally be a special privilege rather than a minor use unless the OC had a great oversupply of parking, in which (unlikely) case it might be accepted as minor.
In other states, even the most trivial alteration might require a by-law and the class of resolution required to pass that by-law can vary.
A by-law could give permission to all or a class of owners to do a particular thing in a particular way (eg install awnings of a particular colour and type, but only on windows of west-facing units).