I have to agree with toejam. I suspect most clerks at Academy don't have the same level of experience and expertise as those at some other retailers. I have had very good experience with REI. The clerks there were extremely knowledgeable and helped find the right boot for me.
Fit is not just size, but also the overall shape of the boot. Different manufacturers vary as to whether they are best for narrow feet, wide feet, etc. A knowledgeable clerk can help steer you to the brands that would be best for your particular feet. For example, my husband apparently has narrow feet even though he buys his everyday shoes in normal widths. Going to a boot that was designed with the narrow foot in mind has essentially eliminated his former problems with blisters and occasional blacktoe.
If the store has one of those little ramps that you can walk up and down, use it when you try your boots. I know I tried the first time I bought boots, but did not know what to do or what to look for. Make sure your toes are not touching the front when you are going downhill or you risk blacktoe or other problems. I go as far as to kick something solid with the toe to make sure my toes do not hit the front of the boot.
I am sure you can find all kinds of things on the web about techniques for finding the proper fit. Here is one that I found in a quick search. I am sure you can find others.
http://www.greatoutdoors.com/publish...tfittingguide/ Note also that there are many different ways to fine tune the fit with different lacing techniques. I don't begin to know or understand all of that. I found a lacing technique that works for me and my current boots, so that is what I use.
Finally, I will throw in my 2 cents worth for Goretex. I know the common complaint is that it is too hot. I am not sure what to say about that. Since it is Texas and heat is usually the issue rather than cold, I chose a lightweight hiking boot that has air mesh panels to make it more breathable, Vasque Mica GTX Hiking Boots. The REI's website this morning said they were $125. Perhaps the fact that they are lightweight and breathable makes them cool enough that I have not noticed the Goretex being a problem. I love the fact that they are waterproof and would no longer own a pair of boots that were not waterproof. I love being able to ford small creeks or other such impediments with abandon. I was afraid that they might not be enough support since they were lightweight, but they have seemed fine to me. They were fine even with over 40 pounds on my back when backpacking in Big Bend. My only reservation concerning lightweight boots would be for clamoring over really rocky terrain. Even that has not been a problem so far, although admittedly most of our hiking, even the large amount of off trail that we do, does not tend to be really rocky or mountainous. A heavier, sturdier boot might be in order depending on exactly what you will be doing.
Have fun boot shopping. Good luck on finding the right boots.