A meditation room has a couple of specific areas that need to be addressed when planning. How and where you'll meditate is a key factor. Do you prefer to sit in a chair or on a cushion on the floor? Or maybe you kneel, depending on where you are in your practice. Whatever your preference, you need to make sure you have a comfortable area to do it in.
If you spend most of your time on the floor, make sure you have plenty of comfy cushions or a mat that can support your stance. If you sit or kneel, make sure you have the right bench or chair to use.
Another common area in a meditation room is a prayer table. This is where you place your altar, which consists of any elements that help you keep focused while meditating. It could be photos of deities or gurus, or maybe just a group of candles. This table provides a focal point to help keep you centered so you can stay on track. If you use music, you may want to set up a speaker system so that the music appears to surround you. Or, you can always just bring in your CD player.