The National Institute for Clinical health & Excellence (NICE) has published blood glucose target levels for Type 2s, as follows:
4 - 7 fasting/before meals
less than 8.5, 2 hours later
These are in mmols/l. Many of us on the forum prefer never to go above 7.8, 2 hours after meals.
Non-diabetic levels are within the range:
3.5 - 5.5 before meals
less than 8, 2 hours later.
To check what different foods do to your blood glucose levels, test just before you eat and 2 hours after you've finished the meal. It's really best if your BG level after eating is about the same, or not much above, the level you started at. If you eat something that spikes you, eat smaller portions or leave that food out altogether.
Don't worry, though - it takes a lot of experience to understand which foods spike your BG levels and which don't. I low-carb, mainly for weight loss but it also keeps my BGs low. See
Viv's Modified Atkins Diet in the 'Sticky Thread' section for a list of my basic foods.
My BGs are now normally within the non-diabetic range, but it's taken 2 years to get there. I'm still human - every now and again I have a blow-out (bread-and-butter last week! in quantity

).
Carbohydrates, which include sugar, do the damage. If you can cut down on those (you don't need to go as low as me!) you'll gradually bring your blood glucose down.
Tell your GP that you are trying to control your carbohydrate intake, and that you would like to have a self-testing kit to help you learn which foods spike your blood glucose - you can't learn that without testing! The NICE guidelines recommend self-testing as part of the structured diabetic education you should be receiving, though many PCTs are restricting test strips as a cost-cutting exercise. If they think you're taking control by diet seriously, they might give you strips on prescription. Cheaper for them in the long run!
Let us know how you get on
Viv 8)