M. C.
Do you attend a church or other religious worship? If so, check there! Ask about a youth group and see if the leader can recommend someone. That would really be the best way, as you'd be getting someone with your own values or at least similar ones.
Another resource I just thought of is to call your local high school to see if they have a program for early education, a lot do. Then ask the teacher for a recommendation or to post a wanted ad with that group. And sometimes park districts have a babysitter safety course where they learn CPR & other good skills, maybe check with the coordinator. But those two would be after the church community in my book as it's less of a blind shoot. You want someone you can trust, obviously.
If you have friends with older nieces & nephews, you could ask if they babysit. I find a good age for sitters is about 15, they don't really have a "life" yet are responsible & capable of taking care of things until you can return. The very best thing I've done with my kids is we put them to bed then start our date later. You have the sitter there about 15 minutes before their bedtime so they know she's there and won't be surprised if they wake up & call out then this sitter comes in. You do your normal bedtime routine then head out. They're in bed & your sitter is able to eat everything in your refrigerator & talk on the phone all night, you know your kids are safe & can enjoy a quiet, albeit late, dinner.
Good luck!
D.