Learn the page flow
Most English manga editions read from right to left, including panels and speech balloons. Give the rhythm a few pages; it becomes natural quickly.
Choose by mood
Start with the experience you want: action, romance, mystery, horror, sports, fantasy, or quiet everyday life. Fame is less useful than fit.
Sample before committing
Try a library copy or official preview before buying a long set. One complete series under ten volumes is an excellent first project.