The general advice is to cut back on
carbs, they all get converted to sugar. My Doctor gave me a target for a daily carb allowance. Since cutting back too quickly on the carbs can lead to complications, this initial target will, along with your medical history, depend on your previous eating habits. The most important thing to note is that you have to reduce your carb intake in stages.
Get into the habit of looking at the nutritional info on prepared foods, snacks etc and don't be fooled by labels that say: "Healthy Option". They may be healthy, but they can also have very high carb content. If, like me, you lack the discipline to just have one chocolate digestive, then it is probably best to avoid high sugar biscuits completely. Ditto with packets of crisps, tortillas and the like. Sugar is another no-no: Avoid sugary drinks and, if you can stomach them , use saccharine or some other sweetener in tea and coffee. If not, drink your morning cuppa unsweetened. With respect to soft drinks, note that there is a difference between "sugar free" and "no added sugar". It is the latter which should be your beverage of choice.
In general, you should only have very small, tiny daily portions of high carb veg, grains and cereals. Basically, cut back drastically on: pasta. potatoes, rice, bread... Another thing to avoid is "most" tropical fruits as they have a high sugar content. Apples and berries have a much lower sugar content, as does fruit which is not fully ripened.
For snacking, tree nuts:, almonds, walnuts, hazelnuts.... are all good. On the other hand dried fruit like raisins and sultanas are full of sugar. (That is why grapes are used to make great wine)
There is a meal planner
here in the main DiabetesUK domain, which may be of use. Along with a search box, the page also has a navigation bar that will allow you to browse a large number of good quality articles on suitable foods, recipes ... etc, etc.