I've reverted the change to Bradleys Head Lighthouse, the other changes seem okay.

No problem making changes, I know accidents like this can happen, so take this as a pointer for next time to watch out for it, and certainly not a discouragement to map. Mapping things from your local knowledge or from compatible sources is fine, if you're unsure about something feel free to ask on one of the community sites (click Australia at https://openstreetmap.community/ to see all the places OSM community is at)

https://osmlab.github.io/osm-deep-history/#/node/1903566739 there are other tags indicating this is a cardinal beacon, by changing it to light_major it looses information that it's cardinal. Are you sure about this change?

the lighthouse you added already existed so I've removed the duplicate you added in changeset/89784100

The iD editor preset automatically adds building=yes, so where you're marking the grounds you need to make sure there is no building=yes tag, you can then add the individual buildings inside the grounds separately. I've fixed this up for the ones in this changeset in changeset/89783972

looks like you accidentally dragged the bus stop into a building https://osmlab.github.io/osm-deep-history/#/node/2626808800 safe to assume that was an accident? I'll move it back.

what's your source for https://osmlab.github.io/osm-deep-history/#/node/247040994 being asphalt, is it from a survey? from the imagery it looks like it could be grass

restored Petersham Reservoir

Move over Pokemon Go edit's this looks like the start of Microsoft Flight Simulator edits...

I've restored the location of YRNS, it's on the hospital building, not the street.

looks like an accidental drag of https://osmlab.github.io/osm-deep-history/#/node/1042094263 so I reverted the change to that node

you could add the building tag, then it will show as a building. an area which is just covered is usually building=roof. Normally I'd tag the whole petrol station grounds as amenity=fuel with all the tags, then a separate building way(s) inside it.

going by the photo at https://www.sydneywater.com.au/SW/water-the-environment/what-we-re-doing/Heritage-search/heritage-detail/index.htm?heritageid=4570350 I'd still say that's a chimney, it's much larger than these smaller metal masts I mapped here.

however I'd still add:

tower:type ventilation_shaft

because it acts as a ventilation shaft,

I added

substance sewage

which is not entirely correct it's not like these shafts are spewing out sewerage, but connected to the sewage pipes and venting gasses so I think it make sense when combined with the fact it's a ventilation shaft.

https://osmlab.github.io/osm-deep-history/#/way/801462122 was deleted in this changeset, however it was added against the more recent maxar imagery and it looks like you're using the 10 year old imagery from 2010.

Next time before deleting or modifying it's wise to check who added it and under what circumstances it was added, and if it was using a more recent source than you.

So I've restored this deleted building now.

Hi there, I've made a note to do a ground survey here to check. As has already been mentioned, just because something is mapped in OSM doesn't mean it implies it's public access, many private access features are mapped as access=private. So it's only if the road has been removed that it should be deleted.

Since it's been a few days now I went in and fixed this in changeset/89621054

I'm interested, help to know how leafy an area is. Don't worry about the map being less readable, in my eyes OSM is a database not a map, if someone wants a map without trees, they can just exclude them from their style. Of course you don't need to map them, but they are welcome contribution.

actually I can just leave that empty eg https://hiking.waymarkedtrails.org/api/symbols?osmc:symbol=%3A%3A%3A%E2%89%88%3Alightblue for the two creeks track here

But osmc:symbol=* doesn't allow me to only specify the text and text colour. There is no way colour or background colour.

I'm not so interested in any particular downstream support right now, I just want to enter the data as correctly as possible for future downstream users.

yeah I just made that tag up now as a way to try tag a character that matches the route symbol.
symbol=* is a good one to use but since it's just a human readable description, it's not exactly the same as providing the exact character.
osmc:symbol is limited to a fixed set of symbols, where in many cases it's easier for both mapper and data consumers to use use an existing character symbol.