That's a tough one... do you have any friends or family that's been through D?
I was in the same boat... no clue how to pick one. Honestly.. I just picked one. She's OK.. I had some problems with her, but we've done good so far and I don't think I owe her much from an hourly standpoint.
Anywho.. They will do free consults. That's what I did. Kind of explained the sitch (they don't care about the details really.. just the legal pieces) and she told me what to expect.
Mine had a retainer fee and charged hourly. The retainer fee was equal to 10 hours of work. Above that, she charges hourly.
I would at the least check what the laws state for you (Ohio right?). Go out and do a search for divorce in Ohio.. there should be a site that has all the legal crap available.
For us, we have to be separated for 60 days. There is a temporary order (kids, alimony, who gets what cars), a separation agreement (division of assets including bills), then D. That's in Ky.
Keep in mind.. if it's an equitable state, you are just as entitled to half as she is. Half the marital bills are hers.. etc etc. It can get real ugly.. like 401K's etc.