I think I'm an expert on sep anxiety at this point. I'm on my second kid. I've never met another kid who has had as much sep anxiety as my dd1. Dd2 (who will be going to K this fall, too) has it to some degree, but nowhere near as much as dd1. They're actually in a small private school primarily because is was so much the better fit for dd1. Last year in the 2nd grade was her first really good year as far as sep anxiety and she did still have issues, but not crying every morning any more. She had many more mornings where it was a quick easy drop off. I think it might be college before she's really ready to go for it on her own every time

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You are almost certain to hear that you should just leave her even if she's crying and she'll stop in a few minutes. This is actually true for many kids and might be true for yours, too. It comes closer to working for my dd2, but is a recipe for disaster for my dd1. I've seen it work great for a lot of kids because I'm the mom that always has to stay.
The Kissing Hand also works well for a lot of kids, but not my dd1. I haven't even tried it with my dd2.
A picture of the family that your child can keep with her helps a lot of kids, but again the very idea of it made my dd1 tear up. She didn't want to think about me while she was at school because she knew she would start missing me too much. This is a really great strategy for many kids, though, so think about whether it would work for your child or not.
Dad dropping off is another good strategy. We tried that one, too. It really wasn't better for us, but I know it works wonders for some kids.
Because we've been in a small private school/preschools we have had a lot of flexibility that may not be available in other settings. In the end the thing that I think worked the best for us with dd1 and Kindy was just the real real real long slooooooooooooooowwwwww goodbye. Like over the course of the year slow. Many people advocate yanking the bandaid off and it really does work well for a lot of kids and parents, but it just didn't for us. You know your child best! I stayed a long time in the beginning of the year. I got a lot of pressure from the teachers to just go ahead and go and I did try that some, but with my particular kid that wasn't a great idea. It worked better to ease myself (and dd2) away. We would go out on the playground and play while dd1 was in her morning meeting (45 minutes after arrival) and then come back to say good bye, etc.
With dd2 she needed a goodbye routine in preschool. Again there was a lot of pressure from the teachers to just let her cry it out for a few minutes and I did try that some, but it didn't feel right to me. It ended up what worked for us was for me to stay through their morning meeting (it started about 15 minutes after arrival and lasted about 20-30 minutes). Then when she picked an activity and showed it to me I could go to the door and she would have to run over and give me a last kiss and a hug. I didn't join in on the morning meeting (sitting in a circle on the rug), but hung behind and tried to fade into the background. I wanted her to find her own way and she did and thoroughly enjoyed it, but she didn't want me to leave and made it clear. It wasn't worth disrupting her day or the whole classroom to push it (she's a VERY LOUD crier).
Anyway, my advice would be to listen to your heart and to your child. You know your child best. The teachers know how the average child is, but my kids aren't average and I know them best. Use the teacher's advice as a guide rather than a rule. See what you think will work best for your kid.
Good luck!