Photograph Your Seedlings
This year I am going to take pictues of all my seedlings that I am hoping will self-sow in the future. This way, when I am weeding I will be able to recognize what I want to keep and what I want to pull.
Cilantro looks like a tomato seedling at first. Last year I actually starting weeding them, thinking they were tomatoes. Won't make that mistake again!
Be patient, and in a few days you will see the third leaf appear, and it will resemble cilantro more then tomato.