Tell us which faction you play, on which server and in which battlegroup, and then report how things seem to be going for you and your side. Do you always win in some battlegrounds and always lose in others? Or is it 50/50? Do you tend to do better or worse at certain times of day? What seems to make for the difference?
Please try to limit yourself to your own actual observed experience, and refrain from conclusions based on assumptions or guesses. I'm not particularly interested in hearing "Because Horde is better at PvP!" or "Alliance is all 12-year old noobs!" because these answers are just conjecture and don't actually convey any real understanding. If you have some kind of practical knowledge as to why your faction wins or loses a lot, however, then feel free to share that as well.