Here are a few rules of thumb to keep your items and value safe:

- Do not download anything sent to you by a stranger. If they claim it is well known software such as Mumble or discord, then use Google or another search engine to seek out the official site for that software.
- Do not click unfamiliar links sent to you by anyone including people you know.
- Check that the spelling of any familiar URL is correct before clicking it.
- Never trust a stranger if it involves you having to give items to him first.
- If a stranger ever asks you to trade your item to a friend so that he can check something, then beware of a scam. There is no reason at all for you to trade your item to a friend in order for a stranger to check anything.
- Avoid accepting cash from Unverified PayPal accounts.
- Avoid trading items for cash with strangers who use comments on their Steam profile page as rep.
- Do not use a middleman that is not from a trusted trading community.
- Beware of impersonators of trusted middlemen or of trusted traders if you are trading items for cash.

A list of trusted trading communities can be found here: https://steamrep.com