how can i find out strengths in me??

it takes a life time to work on ones self to find out these things, there are courses you can take to become more self aware of who you are,

the easiest way is to start by listing what are you good at,

what could you be good at with enough practice or education

what are simply not good at and doubt that you would ever be,


for example

you may be good at playing the piano,

you might be a concert pianist or work in the industry if you had enough formal instruction and years of practice,

but you suck at playing sports and you know no matter how much practice you had at it you just would not be good enough to make it professionally, you are not fast enough or strong enough or both.

this is where you start with the easy things,

then you go on from there,

you never thought you could be a painter but you like to paint? Give it a try see what happens.

I'm not sure that there is a method. I think it is a matter of getting to know yourself and experiencing different things. I would be inclined to spend some time by myself getting to know me. Find out what you like and what you don't like without influence from anyone and the only way you are going to find out what you are good at is by trying your hand at different experiences.
Have you ever tried meditation? It is a good way to quieten your mind and see what comes to you from within.
Good luck!