If you don't think your Real Tracks and MIDI parts sound like they occupy the same "sonic space", it may help to get a small mixer with effects (like one of the Behringer series)
Route the MIDI and Audio into different mixer inputs, and add a light sheen of reverb to unify the whole mix. When played together, this seems to make all parts sound like they're in the same room.
You could accomplish the same thing if you are running both parts into a PA mixer that can add light reverb reverb.
When recording, you can add the reverb to the entire mix at the end
You can train a dog to jump through a hoop by positive reinforcement. But if you kick him just once after he jumps through the hoop, he will probably avoid the hoop from then on. The same principle is true of song writing.