I don't really have a lot of secret ingredients, per se...I do use this a lot:
Tony Cachere (pronounced sasheray) Creole Seasoning
Otherwise I use various combinations of sea salt, tri-color fresh ground pepper, balsamic vinegar, red wine, white wine, ex virgin olive oil.
I do find uses for this stuff whenever possible. I could live off this stuff on crusty slices of bread:
green olive tapenade
It turns an ordinary turkey sandwich into a transcendent experience.