If you want to be successful on youtube, you have to do what you love. Whether that be video games, vlogs, comedy, DIY, you need to have a passion for it. DO NOT do videos just because they are a popular category on youtube and you're just looking to get popular and get a lot of views. Focus on your passion, learn unique skills, do things no one else is doing on youtube, and that will give you both the satisfaction of doing something you love and it will give you a more genuine audience that will like watching your videos for you and be inspired by your work.