For stores like grocery/sporting goods, etc, where there are lots of staff that won't make the decision, I go to the information desk and say 'I really enjoy shopping here and know that SJK believe in supporting our local community. Is there someone I could speak to about scholarships or other funds for school? No amount is too small to have a significant impact. I hope, when I have completed my education, that I can provide the same support to my community.'
This works for a few reasons... normally the person I speak with can't make the decision and just wants to hand me off to someone else, so they will generally give me the phone number and name of someone who may be able to make a decision, or will be able to put me in contact with the official person/program. I admit, only 1/3 of these work, and the amounts might be small, but even a few hundred will help cover books. If it seems like I have reached someone who can make a decision, I may also toss in an offer to do a presentation for, say, dog products for thier associates or thier customers. Or stain removers. Etc. Most will not take you up on this...but it may give them something to negotiate with if they have to approach someone else (having said that, I did give some presentations on Kong stuffing at a grocery store.)
If it is a smaller place, say a dog training academy, or a scuba shop, where there are few staff members, I would try to speak to the owner, and I again emphasize any amount will help, and that I would be happy to provide regular updates emphasizing how much they have helped me (in a format that is easy to hang on the wall!) and to carry brochures with me to distribute. Obviously, this requires an established relationship where you really would be willing to endorse what they are doing...and then you really do need to. An easy way to make sure they feel like they are getting some worth out of this is to write your name on the top of any flyers that you do hand out. I try to be sure these are places I can give specifics about 'oh, go talk to Dave, he is amazing at underwater photography, and Jim is really great at teaching dry suit diving.' or 'when you go, ask for Jane, she does the best puppy classes, but you mentioned an interest in agility. do you think you want to compete eventually? Really, then Ted's class is the one for you!."
It is cold calling, and it isn't easy, but it can really help. Borrowing a library book on cold calling and sales can help you do it. You can't be afraid of rejection...and if you associate pride with not asking for money, you have to get over that. Obviously, on the second one, it helps if you have already sent the occasional person thier way. I also, in those cases, offer to do some of the 'dirty' tasks they may not like, such as presenting at schools or at community fairs...junk that gets thier name out, but can be tedious.
It is also a valuable skill to develop; it has served me through non-profit work, government work, and every job in between. And, in case you are wondering, I was actually painfully shy when I first started doing this. I originally did it to attend a residential consortium HS that my family couldn't afford the couple grand a year for. When I finished that....I thought, why won't this work for college, and really, what do I have to lose by trying?
Just, if you make any promises, keep them. Very important. Also, some non-profits (not normally animal base ones, but youth focused ones, or community focused ones) will toss some money at you with a bit of an expectation that you will give presentations on getting into school and that they can direct the occasional interested party to you.