I'm raising 3, my Mom raised 9, and my Grandma raised 12. This works, I promise: First, on a weekend or evening, practice the routine- and with your daughter, write down how long it takes her to REALISTICALLY get ready. Have her show you how long it takes to brush her teeth, put her shoes on, etc. Then the two of you can talk about the schedule you need to make. Acknowledge that she must not like all your yelling (or however you handle your frustration with her), and that she's old enough to take responsibility for gettiing herself ready. Let her know that if she isn't ready when it's time to leave, you will take her anyway, even in her pjs. If she IS ready, she will get her sticker (happy face, whatever). She's 6- the idea of going to school in her nightie will be enough. Practice the routine again with the timer I will mention below- and no nagging. Just let her practice.
THEN, the night before, pick out clothes, get bookbag packed, etc and put them together in one place- bedroom is ok, but living or bathroom works, too. I wake up my kids 15 minutes earlier than I need to- this is for my own comfort, and they didn't know until they could tell time.
I have a kitchen TIMER that goes off when it's time to STOP everything (breakfast, tv, toys) and start getting ready. Then I reset the timer- be realistic- to leave us 5 minutes before we must walk out the door. You have only 1 child, so you can be more hands on, and not worry as much about taking turns, but give her enough time (based on what she showed you) to get it all done. No nagging, just let her do it. When the timer goes off, she will be ready. BUT... and here' s the clincher....
If she is NOT ready, put her in the car anyway and GO.
This sounds harsh, but you will only have to do it once, if ever. You have to teach her now, or you will fight this all of her school years. Ugh. That extra 15 minutes you gave yourself earlier will allow you to calmly remind her that you told her this would happen, and that she's responsible for doing her part in the routine. Brush her hair, make sure she has shoes on, and kiss her as she goes into the classroom. She'll be fine. And she'll stop dragging her feet! If she knows you'll follow through, so will she!
ps- if it makes you feel better, put a set of plain sweatpants and a tshirt in the car, just in case. Nothing fancy, just not as embarrassing as pajamas.
***As a former teacher, I have to say, please do NOT to make the Teacher have to help dress your child or otherwise be the bad guy in this. She/He has 30 other kids to handle first thing in the morning. This is a parenting issue.