Hi Becky,
A low sugar/low fast acting/refined carb diet is best for hypogylcemia, eating regularly enough so that you don't have a dip, which is usually 2-3 hours.
Good grains would be quinao, millet, buckwheat and brown rice. If you are otherwise in good health with no other symptoms you might be okay with glutanous grains such as spelt, kahmut, oatbran and rye.
Most proteins should be fine and should form the cornerstone of your diet. Beware of pre-packed processed meats or those that are breaded or frozen as they may contain hidden ingredients that you won't agree with, however small the content may be. Also be aware of too much tinned fish and farmed fish in general as it can contribute to elevated mercury levels. Fresh, wild and organic should be slightly better.
Good fats include pumpkin seeds, sunflower seeds, sesame seeds, hemps seeds, most nuts (cashew, almond, brazil, macademia, pine, hazelnut, walnut), olives, oils (olive, sunflower, avocado, coconut).
You'll want to cut out all the sweet stuff, such as...
chocolate, sweets, coffee, black tea, pastries, biscuits, cookies, crisps, white bread/pasta, alcohol, flour etc
Also watch out for fruits in the early stages. No no's include bananas, grapes, raisens etc. You'll probably be okay with lemons and limes, avocado's and green apples.
You might also want to be cautious of certain dairy products. The milk sugar (lactose) could swing your blood sugar and in general isn't very healthy. Look for dairy free substitutes if you really need milk in your diet.
Also be a little cautious of cheese. Whilst a good blood sugar balancer, it can be allergenic if made with cows milk and contain some other nasties. Goats and sheeps cheese is slightly better and might be worth trying.
Also there are some other odd things to be aware of which you will need to guage personally, such as certain root vegetables including baked potatoes, beets, parnips etc. They are starchy and can all swing blood sugar.
Most of the above assumes you just have hypoglycemia. If you feel you may have stressed adrenals, food intolerance, candida, leaky gut etc you might need to restrict things a little further.
Good luck!