You have to play with concepts first and you can start by brainstorming in your own. The mere interest in joining this world would suggest that you actually like reading magazines. Keep up with the reading but complement it with reading articles about what goes on behind the cover stories and what in general is happening to your favorite titles. After that then you can go about observing other people and what they read. Do not stick to one area, go out of your comfort zone and check out what the rest of the people are reading. These exercises will help you a lot in coming up with fresh ideas.
Magazine publishing concepts are bountiful but again a word of caution because it is in pinpointing the one thing that works best for your decided target market that will spell your ultimate success or doom. Upon learning that, make sure that you invest time and energy in coming up with that winning concept. It sound daunting but if you think you have it then do not be afraid.
Rest assured that when you have that concept thing covered then it is safe to say that you are already halfway to making your business work and which can also mean future success is not far along.