How and where ??
If you cannot follow your own logic, then there's more of a problem than an analysis. Try and spot what you're doing, it's good to learn how you think.
How can one follow his own logic ?
Can you give an example??
How can somebody learn how to think??
Can you again give an example??
I mean if I look at how I reason it's simple.
If A is a field, A is also a ring.
B is a field, hence B is a ring.
It's easy to see this is modus ponens.
So just look at each step, write out in words what your reasoning is. If you need to, you can also make a list of the logical inference rules then compare the forms of your reasoning sentences with the list and decide which rule you are using.
As for how someone can learn to think, that's a mystery even to the best psychologists. I recommend just reading a lot of proofs and getting used to how they read, and trying to write some yourself to mimic those. In this way you get practice learning what "good thinking" is like and attempting to duplicate it.