How should you read proper nouns aloud in English?

When people don't know how to pronounce a word in English, they can look it up in the dictionary. However, lots of proper nouns usually can't be found, for example, English names.

Here are my questions:

• When people want to read some English texts out loud, what do they usually do when they get a proper noun that they don't know how to pronounce? Are there any general rules of thumb for such a situation?
• Are the students in English-speaking countries required to read English texts out loud in elementary school? And how are they told to deal with the problem I mentioned above?

The general rule of thumb is to read it as you would any other word, i.e., follow normal rules of pronunciation. It'll work most of the time, and when you're off, you'll be told the correct, "unorthodox" pronunciation.

I can't speak for all Americans; however, in my elementary school we did read texts aloud, but rarely. And I don't remember specifically being taught how to pronounce unfamiliar proper nouns.

I say don't worry about it too much--if it's unfamiliar to you, it's likely to be unfamiliar to many others. In this case, no one will fault you for not knowing how to pronounce the word; as you said, it can't be looked up in a dictionary.