I've got a few pages to catch up so sorry if this has already been covered.
When I was hunting around for my best fit type I found this approach was very helpful. I read about the behaviours that go with the dynamics of a type I was drawn to in a respected source - a reliable book or web site. I noted the interactions between the primary and secondary functions as well as the way the type is described in the round. Then I tried behaving like that type, consciously and deliberately - wore it for a bit just as you might try a new outfit.
Particularly if it's different to the type you have thought yourself to be before, it may feel strange - it's quite possible for our preferred functions to be displaced so that they feel odd if we've been mistyped for a length of time. It's also possible that you haven't had a clear idea of what these functions actually feel like - I was pretty clueless about Ni from the descriptions until I experimented with it, then found I'd always been using it but hadn't connected the name with the inner experience before. If you have picked a good fit, then after a while you will find that you feel at home with it, and it will seem to align well with your energy - you will be able to relax while behaving like that. If it isn't a good fit then you will become very tired and a little stressed while keeping it up, and find that you need to wind down by changing to a different sort of behaviour - in fact you will find your behaviour slipping away from it. Be a little careful with this because our secondary always takes some conscious effort and can be tiring too, but it feels ready to hand, and good, and brings energy as well as taking it.
Don't get too serious about this if you try it. Use the sort of attitude you take with you on holiday to a place you haven't visited before - fun, exciting, some effort, interesting. Keep a good sense of humour close by too ....
My feeling is that if you try out a type and it fits you comfortably over a period of weeks and months, then you have found your best match. You will have the inner confidence that comes with this that means you won't get de-railed easily by others' opinions - they will be interesting, but won't threaten your sense of who you are.