Here's an oldie but a goodie...
One fundraising tip I think works well is really not a fundraising event. Generate a list of your current donors, with phone numbers. Divide it up among your board members, some volunteers, etc. Have them call your donors and say this:
"Hello, Mrs. Jones. I'm from XYZ Clinic, and I am just calling to thank you, as you have been a faithful supporter of our clinic and have been a big part of why we were able to serve xx,xxx patients this year. Again, just a thank you call, nothing else. Can I answer any questions you may have?"
Then SHUT UP and listen... After they pick up the phone from dropping it in shock from you not asking for money, answer their questions. If they have none, just thank them again and hang up.
If they say something like "you're not asking for money?", say "while we need everyone's continued support, the purpose of this call is to thank you for your support, and that's it"
This is a great way to get your board involved in actually doing something (!), as they won't be asking for money (which is their job, but they all hate it - more on that later).
You don't have to call all your donors, and you could spread this out over the course of a year...
Just a quick tidbit.