The first and most important rule of avoiding telemarketing fraud is to watch out for uninvited calls. You should avoid giving information to people who call to pitch or plead with you to give them money. This includes people who claim to be well-known companies or charities. For example, if a caller claims to be your bank and insists that it's important, you should hang up and call back using a number that you know is legitimate.
The FTC checks millions of reported cases of telemarketing fraud every year. You can have it warn you about scams that you should watch out for by signing up for Scam Alerts. You'll get notifications by email warning you about the latest scams and how to avoid them.
It's also important to watch out for people who offer free trials of popular products or services. These free trials typically require you to provide your credit card information, which allows fraudsters to steal it. Even some legitimate companies count on you forgetting about canceling free trials so that they can continue charging fees every month.
Use this information to protect yourself against telephone fraud. If you think that you've been contacted by a telephone scam, report it to the FTC so that it can warn others.