There is nothing wrong in asking for what you want! We decide in advance whether a meal out is to be a protein meal or a starch meal - if you want to keep the price down, or make your choice easier, go for the starch meal!
You can ask for fresh fruit or vegetable dishes without any thickened sauces with either protein or starch meals.
If you select a protein meals, avoid battered fish, pies and pizzas. Plain fish is often the easiest as it is usually served with an unthickened sauce. Roasted and grilled meats can be requested without the potatoes or rice that usually accompany them and I always ask for extra vegetables instead. Fruit and cheese can round off a restaurant protein meal.
Starch meals can again start with fruit, or with garlic bread. If there are a selection of vegetables, I order these without a main course, together with potatoes or rice. I find the tastiest end to the meal is again, often fresh fruit.