It is hard sometimes. I know you are at a different school than what I went to, but there might be a similar class. There was a physics writing class where we presented results in a slideshow after performing an experiment. It was more geared toward the "business" aspect of presentations. However it is possible that business majors never take a similar course in business presentations, because sure as heck every company meeting I have been to they read directly the words from the screen verbatim where the audience sees, and you are taught not speak exactly what was written. A possible elective course for ya??
...I guess that means learning what to say and what not to say will help. One recent that was a no I realize after it was because I used the words "wouldn't mind". I should have only said "I hope I can detect the yard". That, and prob asking for her by name might have caught her off guard. I knew it from the assessor site, but saying it prob automatically put up her guard...who is this guy and how does he know my name?. Be short and to the point. Don't get onto whether or not finds will be split unless it gets mentioned by owner, cuz then they will automatically think 'Oh my yard can have a buried gold treasure in it? I wanna find it myself'. Pointers should you want to use them. It is always a little awkward, yes, but some people just have that charisma where they can walk up to anyone and talk to them no problem. The main aspect I feel holds weight is that you have to ask to be at ANY old house. You don't need permission on your own property (altho that is not always 100% too), You don't need it at public parks (with many being subject to ridiculous rules or some banned not even due to a detectorist not filling holes)..but to be able to do any old property with a standing house you need to ask. As like a requirement. Or chore. Something you don't want to do but you know needs to.
Like others have said, there are always other places you can detect without needing permissions. I have a bunch of those, too. Mainly I have those when it's spur of the moment I get a text to get out after I finish work and we need a place quick. Driving around from place to place can kill the amount of detecting time you have in an afternoon. Esp now the days are about an hour earlier sunset than it was in June. And not always will you get the best luck at a permission house either. That's what some don't get. The aspects it has going for it are that the house hasn't fallen yet and being a permission: not everyone can go there and swing away. But it too is subject to yards being graded and reseeded, fill being added or dirt removed, or a lot of trash. Roofs and siding (or shakes) have to be replaced from time to time and there's bound to be dropped nails. People have parties or gatherings and there's bound to be a few bottle caps. I littered my fire pit area with nails and staples by getting rid of my 60 year old cabinets. Many of these houses burned down and were rebuilt on the existing foundation. Not just from candles either. The early wiring too in the late 1800s burned many houses. Obvi you know what that means, but being a forum Ill explain that it means trash from the old structure being removed and new construction trash will make hunting these places a little tougher. So don't be as strung out about not wanting to do it. There's always a gamble when checking any site. Losing out permissions, or not asking as you mentioned, may not be that bad.