Effective security means a different notion of what's allowed in carry-on luggage, and what should be left to checked luggage. If you have a question about a potential item in your carry-on luggage, use your airport's customer service for guidance.
The most impactful regulation might be in liquids and/or gels. The Transportation Security Administration calls this rule "3-1-1": 3 ounces or smaller in a container, 1 quart-sized zip-top bag to hold those containers, and 1 bag allowed per traveler. Otherwise, travelers are supposed to store those liquids in checked luggage.
Here are just some of the items prohibited for airline passengers. A full list is available through the TSA: