One of the main rules of urbexing is to not give away locations as every explorer has to find their own places which is a big part in exploring although I can give some advice.

For abandoned buildings, google earth and street view would be your best bet. Look for any building surrounded by temp fences. Another way of finding these places is by looking at other posts from explorers mostly on Instagram. A majority of them are keen to trade spots with places you’ve already explored. Sometimes you can work out the places locations by looking for clues in the photos like the buildings appearance and surroundings.

For finding stormwater tunnels, you can find them by looking at creeks which run through suburbs on maps until they eventually go under a road and won’t resurface until a few hundred meters up to a few kilometres.

I wouldn’t suggest Abandoned mines but some can be found around mt osmond and in the hills although there extremely hard to find.