We just took QR Business class Qsuite (unprepared last minute flight change pushed us onto QR instead of Finnair). A few things to note, one way to tell if your aeroplane is currently a Qsuite plane or not is your seat map. if 1A, 2B (no 2A) exists on a 777, it means QSuite. This can change so don't fully take it for granted until much closer to departure.
Q Suite itself, half the seats are backwards facing by design. For example I was in 1A and that is backwards facing, but my partner in 2B was forward facing. The backwards facing at closer to the window. The seats in the middle are either together (backwards) or apart (forwards). Ask your flight attendent when you board to introduce you the features of the seat when they come around to introduce themselves, they're generally all willing to help show you all the storage bins, nooks and crannies. Also if you are inclined, when you know your actual aircraft, you can can look up if it has Starlink or not - if it does, you'll have the fastest internet that you've likely used - its generally faster than the average NBN at home.
Qatar has some excellent catering so I'd definitely try to eat onboard rather than in the lounge at Australia. The things you can take home - the PJ's, amenity kits and slippers along with the small white pillow- the other big plump pillow stays on board. Right now QR has the F1 themed stuff so if you're into F1 they make great souvenirs too (there's even an F1 livery plane which spotters are all chasing). Just be aware it adds a bit of bulk if you want to take it off the plane with you and if you're travelling having extra sets of PJ's and cushions will need you to figure out where to store it. Whilst they say Amenities kit, it's more like a sampler bag of goodies than practical amenities. Things like toothbrush and such are available at the toilets instead.
Doha can be a huge airport and very overwhelming. It's both big and has LOTS of people if you arrive during their main transit time (late night local time). There are separate transit lanes for business class and your shiny silver boarding pass is all they need to see to let you in. (other classes don't have this boarding pass). I'd recommend looking up where the al mourjan business lounge are ahead of time so you know which one to go it. It's definitely a sight to check out. Be prepared that it can be very busy during the main hub times.
Also for shopping, I found just about everything around so if you're inclined you can do all your shopping from the fancy brands around.
Above all enjoy the flight. Whilst those on the forums here can sometimes moan and nitpick business class products, overall they're all going to be great coming from economy. Just remember to feel free to ask staff if you're unsure about anything.