How did you find NPs to shadow?

First, I think there are dozens if not hundreds of threads that give suggestions on this. A search on the website would probably give you alot of suggestions that would be beneficial.

I think you can boil it down to networking, and the earlier you start, the more contacts you make the more your network spreads. That can be good or bad, you never want to make a bad impression, because that will spread just as fast or faster than your good deeds will.

You will get alot of suggestions, Join NP organizations, national, state, local. Do any and all, but don't just join them, participate. Find other providers (they don't have to all be NPs, providers talk) and make a good impression, let them know what your doing, let them know you will need preceptors in the future. It's not all you will probably need, I've had several occasions when I needed references, or someone to interview for an assignment, or whatever. Try to make it a win-win situation.

Volunteer to help in community health clinics. This falls into if you rub shoulders with someone they will remember you. It doesn't have to be a community health fair, it can really be anything. It doesn't have to be in your specialty (although it helps), as long as you are there and get to meet them. Again, the more you make an impression, the more you connect with them, the more likely they are to remember you and be able to help you when you need it.

Each community and each person's situation is different, but in any case you will have to go out of your way to make the initial contacts, and get them to want to help you. But the more you get yourself in front of providers, and the more personal the connections you make the more likely they are to pay off. That doesn't mean you can't just send a few letters and find some preceptors who are willing to help you out, there are folks who have done this. But put yourself in the other position, you know someone who has worked with you in a volunteer/community/church/whatever project before and is asking for your help vs. you got a letter from someone you have never met (or at least don't remember meeting) who is asking for the same help, which one are you going to reach out and help?