Just a disclaimer that I didn't take BEC in the new format. But, from my experience there really isn't a secret to passing BEC. It truly is totally random and all over the place. I can't speak for the sims, but the writing portion is just luck of the draw. Make sure to just study everything. I wouldn't worry about going super in depth with every single topic, especially with calculations. But make sure you do cover everything, know basic calculations, and at least have a good base line knowledge. Financial ratios, IT, cost accounting, etc. You'll probably see a little bit of it all.
I don't say that to make you nervous, because of the 3 I've taken I still think by far BEC has been “easiest” (if there was such a thing with this exam 🙂 ). Just make sure to be fully prepared to see anything.