How to make your own glazed cherries?
Making maraschino cherries is a bit involved... basically, you brine them and then flavor them. To keep them for a long time, you'll also need to can them. 

Here's a great recipe for making the cherries, and here's instructions for canning. 

The canning instructions are specifically for cherry topping, but you would use the same boiling-water canner process for maraschino cherries in their syrup. 

To pit the cherries, I'd advise purchasing a cherry pitter (yes, there's actually a device for this) if you're going to be doing this very much.