Two Important Steps to Make
There are two steps I have made in my thinking about socionics that I consider particularly productive and highly recommend others follow:
1. Think in terms of functions, not dichotomies
It's initially easier for the mind to divide up people into two halves in four different ways and get 16 resulting types than to think about 8 possible positions of 8 different psychic functions. However, I have found the second approach to ultimately bring much more clarity and functionality.
Each of the four basic dichotomies is very "diluted," since it captures 8 types who express the dichotomy in 4 different ways. For example, among sensers we find those with as the first function, as the second function, and as the first or second function. That's four very different manifestations of sensing.
There is much more to be said about types with base than about sensing types in general. If you create adequate dichotomy descriptions and see what they alone can say about any given type, you will get a much fuzzier picture than if you approach the type functionally. A very large part of each type cannot be explained through the four dichotomies.
2. Understand that psychic functions are working mechanisms and not static personality traits
"You can't be an ILI. ILIs don't say that" is something you might occasionally hear among socionists and enthusiasts. There is a very strong tendency to assume that type behavior is more limited than it actually is (this is strictly my opinion). "Such-and-such a type is good at this, such-and-such talks like this," etc. etc. This kind of thinking comes from the unconscious assumption that psychic functions describe unchanging traits rather than being the mental modules I believe they are.
Each of us has all eight modules and uses all of them. This, I believe, should be understood concretely rather than abstractly. When you're interacting with people in a certain situation, you're using one or more of those modules. In different situations you tend to use different modules. In the course of the day you may switch back and forth between many or most of your psychic functions. Within a conversation, you may touch on many different kinds of information and briefly activate the many different kinds of thinking that are accessible to nearly all humans. In most situations, after you are used to people, you can identify which psychic function (or "IM element") they are using and which information aspect they are focused on. The aspects may change minute by minute and second by second. One almost never has a conversation where one presents information only through one's strongest functions, which is what the static view of personality type would suggest.
When people "get into" an information aspect, they adopt the mannerisms of that function. This means that people can pretty much say or do anything given the right circumstances. However, their subjective experience of each of these functional states differs (and their skill and confidence level - which are visible from without), and they will tend to avoid heavy use of certain psychic modules and be eager to use others.
Thinking about things this way helps to preserve a flexible view of human behavior, concreticize socionic knowledge, and understand what is going on at any given moment.