There are a few different approaches you can take when you’re an intermediate (/advanced) student and you want to improve your grammar.
At your level, you’re looking for two things:
A. Grammatical constructions that you haven’t encountered yet (new stuff)
B. Grammatical constructions that you’ve learned incorrectly (old mistakes)
For the New Stuff (A), you can:
– Work through a frequency list of the top 1000 words in your target language with a tutor. Many of those words will be abstract function words, and the process of creating sentences with them will show you a lot of new grammatical constructions. Learn them using your flashcards.
– Read a book and note the times when the grammar is surprising to you. Learn those sentences with your flashcards, or take those sentences to a tutor and create NEW sentences that use the same grammatical constructions.
For the Old Mistakes (B), you can:
– Ask your tutor to correct you EVERY time you make a mistake when speaking. Write down what you *should* have said, and learn that sentence with your flashcards.
– Write and get your writing corrected (via a tutor or via lang-8.com). Writing is pretty ideal for finding holes and problems in your existing grammar, and corrections are pretty ideal for fixing those issues. Turn all corrections into flashcards.