I'll add a couple things to what's already been said. Do a ride along. You will typically see a boring day when you do a ride along as opposed to an action packed day (just the way it works) but you will see it from the cop's perspective. I didn't mind ride alongs if they were interested. I hated doing ride alongs when they were students who were getting a CJ degree and it was required and they had no desire to be there. Use the time on the ride along to ask questions.
Do the Citizens academy as well.
I would say, don't bring food to a police station because most of the cops won't eat it anyway. Not unless they know who it's from and trust that source. Instead, if you're in a restaurant and you see some cops eating, buy their meal. It can be anonymous or not. I've had that happen to me and it is a very humble experience. Knowing that someone just paid for our food because they wanted to express their appreciation. I'm not saying to do it all the time, but when it happens, it's a good feeling. Kind of recharges the batteries. We had it happen once after a rough day and it put a spring back into our steps knowing the entire world didn't suck.
But mostly, it's the simple stuff. Know where you are when you call 911. If you see something suspicious, go ahead and call and give as much detail as possible. If you see an accident and it might look like someone is hurt, stop and see if you can help. Basically, just be a good person. We sometimes forget that people are good because we only deal with the bad so when we do encounter a good person, it reinforces why we do the job.