Come on guys, it ain't rocket science. There's loads of stuff on here to help get you through. BA selection is always about giving good examples to the questions in the interview, No examples..no job offer. Openness and effectiveness to getting to the goal in the team stuff. A bit of mental maths and verbal reasoning tests (lots of good places to practice those online), and then the sim (lots on here about that too).
Despite what you may think of the process, that's the process, and there's no secret to it.