Suggestions on counting calories and "Accounting for the con

Anyone have a suggestion on counting calories on food that does not have a label?

Example: I love the naan bread from this local restaurant. They cut it into a variety of sizes and I have not idea how it compares to something you might buy from Trader Joes.

This could be expanded to any restaurant food that is not prepared by a chain type restaurant.

What about calorie counting on simple things like sugar or salad dressing. I don't typically walk around with a set of measuring spoons and I know these can add up.

Now that I think about it, what about ketchup and syrup. Does everyone just guesstimate?