Diabetes is a very variable disease, it acts differently in different people. So it's hard to say what you can do to improve it - but at least you can try various things and see the result!
Do you know much about carbohydrates? You can find out the carbohydrate content of the foods you eat. Some diabetics find a low-carb diet very effective.
Don't be afraid of insulin, it's not hard once you get used to it. I don't believe in using insulin as "band aid solution" for an unhealthy lifestyle, much better to improve your lifestyle, but sometimes insulin is inevitable (both in advanced cases of Type 2, as well as everyone with Type 1) and going on insulin can improve your sugar control significantly. If you're already eating healthy and exercising and managing the stress in your life, then maybe insulin is a good idea. Once you go on insulin you can still try other ways to improve your health and maybe you'll stop needing insulin.
Cheers