First- Pick a culture! It’s the easiest way to start, when you know what culture you want to teach then narrow it down. If you are doing a unit plan then choose more than one area of the culture but if it is just one lesson, narrow it down to say a game, song, and maybe a rhythm for the students to play on instruments and sing a song with.
Second- Plan your lesson accordingly, start off with what you need to do first (useful if you are preparing for a general music concert or need to do announcements) and then move on to the fun stuff. Try to do some sort of movement activity first just to get them up and moving around. This helps a lot with their attention when you have to sit them back down and continue your lesson.
Third- Make sure that when you are planning your lesson that you know the history and general background of the activity you are teaching them. Especially if it is a song or dance because the students ARE GOING TO ASK. Even if you have to make up a few facts about it, as long as they get the general truth they are good to go.
Fourth- You can take everyday activities you have used in your classroom before and relate it to world music, you do not have to reinvent the wheel when you are planning a lesson on something new!
Fifth- Be interested in what you are teaching, this interest can come as you research. Also, HAVE FUN. The students are more interested if you are excited about the subject.