If you want to start thinking globally, you should just pick up a textbook. It may come across as a little bland, but a current textbook will give you some idea of how scholarship thinks about the content at a very basic level. From there, you can identify the parts of history you're most interested in and work from there. I've taught a world history class twice and have used two different textbooks. I rather like Patterns of World History by von Sivers and Desnoyers. It's in its second edition, but you could probably get the older edition rather cheaply.