What is the most important basic information that someone starting to learn Latin should know?

Answer 1

I would say that before you learn Latin, you should have a firm base in English grammar, for example, knowing what nouns, verbs, adjectives, participles and gerunds are. That will make it easier to understand some of the more difficult parts of the language.

Answer 2

I think the main thing that you need to keep in mind is that Latin is an inflected language. In English we rely heavily upon word placement to derive meaning. Latin is much more malleable. Case endings dictate how a word is functioning within a sentence. If you are just starting out, my advice would be to learn the declensions backwards and forwards as soon as possible. It will pay dividends down the road.