What is learning?

You are supposed to bump into a range of grammatical rules when you study English for the TOEFL test. To be more precise, that is what we call “studying.”
When the subject is “he” and it is used in the simple present tense, the verb “like” should be “likes.”
When an adverbial clause represents time or conditions (led by “if” or “when”), the future tense should be replaced with the present tense.
There are too many rules to count.
What really matters is whether you are conscious enough about these rules when you actually read / listen to / write / speak the language. When you actually use the language in front of other people, there is no need to worry: nobody counts your mistakes after all. Even when you take the TOEFL test, the rater does not count your mistakes (don’t you think that is impossible considering the fact that the raters are responsible for an overwhelmingly large number of papers to grade?) 
However, as far as my observation goes, lots of learners do not even care about their mistakes when they are studying. This is wrong. They will not improve unless they reflect on what they have been doing and change their attitude a bit. For example, many learners just skip the sound of the plural “-s” when they read aloud or speak. Even though they are reading aloud the text, they do not pronounce “-s.” 
I do not think they are ready to write English or understand the undergraduate level texts.
This tendency is even strengthened by daily practice when learners are encouraged to say whatever they want, regardless of inaccuracy of their utterances. It is easy to think of a classroom situation where a student does his best and makes a cryptic remark in English, and then the teacher applauds, saying, “Good job!” It is not a good job.
Why do you use the language in class? It is because you need to be aware of those possible errors you will make the next time you use it. That way, you are preparing yourself for the actual test.
The TOEFL test is very strict. It gives you a number (a score). This score reflects your language ability. If you are to improve your score, you need to improve your language ability. It does not involve ignoring errors.