For starters, create a catchy channel title, description, profile picture and channel art. Then I would set a featured video - something that lets people know what you are all about. Keep it relatively short ... around 1 minute long.
I would also remove any extra boxes to make your channel look cleaner. The most common ones to get rid of are recent activity & favorites.
Do not upload videos that are not related to the theme of your YouTube channel. The viewers will keep coming back because they know what they can expect from you.