Flying for the first time alone?

I am 18 and have flown before in country and out of country, but always with other friends, or groups or family members. The last time i flew was last February to Mexico and March to Ecuador. I know it must be different flying in country. Are there any tips for what NOT to bring in your carry on besides the obvious explosives. Can we bring like cell phone chargers or will they think the cord is going to choke someone or set a bomb off. Any tips?