There are so many things you could do! You could do vlogs about your lives, you could do videos where you you discuss themes of our time in a critic way. You could do pranks, you could do tutorials (basically on anything, but some ideas are baking healthy food or just delicious food, diy's, games, makeup). You could do comedy. The possibilities are endless. But when you find the things that you really enjoy doing it stick with it because it will probably what you'll be best at.Good luck!