To kind of echo what was said above I frame my door openings 2" over call out in both width and height in order to accommodate 3/4" door jambs. So if your using 2x material for your jambs the width of your rough opening should be 35 1/2" and the height about 84" depending on what you are using for a threshold. It's important to leave some clearance for the bottom of the door to swing in and over a rug if you plan on having one to wipe your feet. Often times on a prehung door that has the threshold built into it I will nail a 1x on the floor for the door to set on so that when you open it, it clears the rug.
If your building your own prehung door a 1/8" gap/reveal is good on sides and top and again just plan for the threshold thickness on the bottom. If you put your door stops in before you set the door just tack them with a few nails in case you want to adjust some for weather stripping thickness when all is said and done.
Rough opening in the framing should be at least 1/4" larger on top and sides so you can adjust the door when setting, then use shims to fill the gaps where you are nailing/screwing thru your jambs and into the framing. Important to level and plumb your door when setting but you also want to make sure it is square as well by pulling diagonal measurement to make sure they are the same. Being square trumps being level and plumb in my book since the building you are setting the door in isn't always level and plumb.
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