Could anybody tell me how to overcome these second language users' struggles?

[NewAgeEnglish]

As a second language learner, I constantly feel there are too many things to pay attention to. For example, when I make a sentence, I have to make sure all these things are correctly put:

The subject is a singular or a plural noun
Should verb be with or without 's'
Should it be in the past or future? and then choose a correct form
What preposition should be used, in, on, or at? Is it of something or for something
should I use he or she, cause in my language there is only one word in speaking for both of them

Above all these I still need to find correct words to express myself, a good phrase to sound a bit more sophisticated, move the parts of the sentence around according to the rules of simple or complex sentences.

All these need to be done in milliseconds! Writing is easier, cause I can always go back and correct mistakes, only if I had enough time. But for speaking, I am really struggled. Of course, I need to make more sense and be more coherent in writing, whereas in speaking, I suppose individual sentences are being assessed more intensively.

So, my question is:

Is there any way people like me can actually develop that authentic sense in second language?
Are there actually any lingual genius around who can naturally grasp all these?
And do English speaking people never or seldom make mistakes on the above areas when they speaking?

[Donna]

Think as if English is your native language.
Do you always sound sophisticated, do you ever make mistakes? Or do others?
Yes, you don't think of grammar or prepositions, but not because you've learned them, because you're used to it. It comes natural Some people are not as educated, they do make mistakes in their native language.
I'd say practice makes perfect. When you've practiced a lot, you don't think whether it is right to say "he work or he works", you just feel like "he work" is so wrong, like how does that even sound OK!