I had to ask for a raise at my last job, because it was clear that they weren't going to offer one. I simply put together a few numbers from the two big salary reports(Propilot and NBAA) and decided where I wanted to be. Then I just asked the CP. Arranged a time to talk about it and made my case for the raise. He agreed and passed it along to the boss.
Here's the downside to working for wealthy people. They remain wealthy by not giving money away. I did get a raise, but it wasn't what I wanted and the raise I did get came with the following statement: "We love the way that you do your job and interact with the passengers, but this is all we can pay you. We understand if you need to find a new job."
So that's what I did.
To more precisely answer your question, just do a little homework about what others are making for similar equipment in your area for a similar size company and settle on a number. Ask for what you want but know before you ever hit the room what you'll take. Then it's a matter of scheduling a time to talk with your boss about it and make your case. I wouldn't worry too much about what others have done within the dept if you don't already know. Just blaze your own trail(tactfully, of course). Good luck.