Can anyone give me some advice on the FTI numerical and verbal reasoning test?

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!

You can find plenty of examples online. I'm also happy to share a couple as well. 

Preparation aside, the most important thing that you have to focus on, is to prioritise accuracy over speed. Some tests have negative scoring for wrong results, so you should instead aim to always select the answer that you're at least 80% sure is right. Don't aim to go as fast as possible through all the questions, but proceed from one to the other quickly while retaining an 80% confidence level. 

Best,
Cristian