Initially just cutting out all the obvious foods which are high in starches or sugars (without counting any carbs) had reduced my levels to pre diabetic within 2-3 months of diagnosis.
My aim has been to reduce carbs to a level where (a) I can maintain suitably low glucose levels and (b) eat a long term sustainable and healthy low carb diet. My meter tells me whether I'm managing this or not, and I find that between 20-50g a day works well for me, but you have to discover for yourself how many carbs you are able to tolerate to reach the level you need/want to achieve - all diabetes is not made equal.