Lucky for you the FTI test, the McKinsey PST, BCG Online Test, Bain SOVA test, etc. are all quite similar so you really can leverage the practice tests for all of them in order to prepare:

The best way is to really find online tests / questions and practice. Regardless as to whether is a new or old test, the principles are mostly the same:

• Time management (need to think quick)
• Business knowledge/context (incl key formulas)
• Critical thinking (answers that are very similar to each other...clues "hidden" in the text)
• Ability to interpret data/charts

Think of it as a merge of a case and the GMAT/GRE.

You need to be clear on some key case-related and account formulas (margin, growth, breakeven, etc) as well as be good at critically understanding the question (including nuance to questions) and parsing through complicated text with a fair amount of distraction.

You'll also need to be good at chart/graph reading.

PRACTICE TESTS

The (old) McKinsey PST, BCG Online Test, Bain SOVA test, etc. are all quite similar so leverage resources across all of them.

• https://www.myconsultingoffer.org/case-study-interview-prep/bcg-online/
• https://www.shl.com/shldirect/en/practice-tests
• https://www.psychometricinstitute.co.uk/Free-Aptitude-Tests.asp

I have a ton of resources here so feel free to reach out for support!