I've found that I can tolerate around a maximum of 50g carbs a day, so aim to keep (often well) below that. I've eaten and enjoyed a low carb/ketogenic diet since diagnosis over six and a half years ago. My only diabetic medication was metformin, which I've not needed for the last three years.
Using my meter (initially setting myself target ranges) and testing mainly pre and post meals showed me what I could/could not eat to reduce and keep glucose down to low pre-diabetic levels. Since I started testing I've seen a regular pattern with highest levels early morning reducing to lowest before evening meals.
Now in general any higher glucose levels are due to things such as illlness, pain, some medications (e.g. statins which I've refused to take, steroids), stress, etc, and not by what I eat.