Some use music to clear their mind and reach a meditative state. This music is mostly relaxing and calming. Clearing your mind, after all, can be the hardest part of meditating.
The flame of a candle can be used in many ways. Most meditation revolving around candles is focusing your thoughts on the flame. Your mind clears itself and focuses on nothing but the flame before slowly losing touch of the flame and slipping into a meditative state.
Just meditate. If you can clear your mind of everything on your own then do that.
It would be good to understand why meditation is often considered important for a practice such as projection. Clearing one's mind, breathing, using labrynths, matras, mandalas, music, candles, and visualizations are all just methods to achieve a meditative state. In essence, meditation is getting into a state of mind closer to the subconscious, as it understands energy far better than we consciously can. When it comes to any area of Magick, your best friends are research (cross referencing and validation of sources), understanding, and your own intuition. Don't just take my word for this; go and figure it out for yourself.