First off you need to do some research on the animals and outfitters/ranches in the area that you are planning on hunting.  Such as, are you satisfied with a smaller animal or are you after a animal that is going into the trophy books.  You also need to see if the hunt is on private property, public property, or both also just how much country is involved in the hunt.  What kind of hunt do you want?  Do you want to ride horses 20 miles before you begin to hunt or do you want to hunt out of a vehicle?  Are you happy with a tent or do you want a cabin with hot and cold running water and a indoor toilet?  You can pull up a list of outfitters on Google for the area that you are interested in and then from that list go to the state outfitters association and see if any of the outfitters that you are looking at are on their list.  Also check out the BBB in the area that you are planning on hunting and see if any complaints have been filed through them on the outfitter that you are looking at.  Then get a list of hunters that have hunted where you are planning on going.  Send them a email telling them what you are planning and if it would be OK with them for you to call them, most of the hunters will return your email with their phone numbers for you to call them on your dime and talk to them about their hunts.  Don't ask them about the size of the animal but get down to the nitty gritty of the hunt such as food, sleeping accommodations, the guides attention to what you expect out of the hunt. 

Pick the outfitter/ranch just like you would pick a new car or truck or even a new home.  Don't just go by a fancy web site and low prices.  Also remember one thing, there is NO GUARANTEE on a trophy animal unless it is a high fence pay for the score type of hunt.  I would even shy away from the ones that say that you will get a shot at one.