Action Alerts Plus portfolio manager and TheStreet's founder Jim Cramer has learned a lot over his 30+ years of investing. So he created a list of 25 Rules for Investing that can help you avoid the novice pitfalls that even he fell into on occasion.

Like believing everything you hear on TV.

Rule 21: Be a TV Critic

"Lots of times, executives say whatever they want on air, knowing that they can get away with it. Lots of times fund managers come on air and tout their holdings without even giving a care about whether they will be in it short or long term," says Cramer.

Let's face it, just because someone says something on TV doesn't make it gospel.

So be skeptical

And listen to Cramer talk about Rule #21 and how the TV vetting process is not all that. 

Sign up and watch Jim Cramer's 25 Rules For Investing here!

And for more Investing Rules, watch these: