hey, im 3rd year BAppFin. My advice is do as many core subjects as early as possible. so if you havent done any second year econ, i'd do that. Or, if you have, econ350 should be ok semester 1. I havent done it but the lecturer, Sean Turnell, is good and shouldnt be too hard.
If you leave your third year core stuff till the end its a bitch cause of time table clashes. Like, of the 9 units you can choose from in 3rd year all of them are only run in one semester each year and most of them only one lecture stream. For instance if I want to do accg329 this semester it clashes with econ350 and acst300 and nccw acst305. But the only other core is fin310. On the other hand if I skip 329, then in 2nd semester cant do accg352. That only leaves accg353, which is a shocker from all reports.
So anyway what im saying is get on top of core units early. Theres plenty of time for electives. But some suggestions are accg201, also phil137 or phil264 or anything outside of efs is good because usually mostly essays and less pressure at exam time.
Also accg253 is pretty challenging and important too because you will need what you learn there for lots of later finance units. My biggest mistake was just cruising thru that subject, not really taking much in just enough to pass.