Hello and Thank You for using Just Answer. I am sorry to hear about the problems that have arisen with your three year old daughter. Her behavior is a manifestation of jealousy of her 10 month old sister. Since she cannot actually say, "Mom or Dad...Please play with me. Please spend more time with me. Why did this new kid invade my space? I was the queen. Why does she get all of these baby things? What about me?"
What your daughter is experiencing is completely natural for her age. She simply wants ALL of your attention. Since she cannot have it because of the 10 month old, then she resorts to acting out in a negative way in seeking your attention.
Nonetheless what you must do is to focus on the times when she is good and really praise her. Keep a sticker chart on a calendar or on a piece of fancy decorated paper. When she has a completely good day, or you can break it up to AM and PM, then she receives a sticker. After about 6-8 stickers, she receives a special small treat or a special outing with just you and not the baby...like to the park, beach if nearby, playground, friend's house etc. Your goal is to replace the unwanted behavior with a desired behavior.
On the other hand, she probably will still whine and misbehave so this will take time. Be patient and consistent. When you set boundaries and give her rules, talk to her at her eye level using simple sentences with more one syllable words and have make her repeat what you have just said. Examples: Do not hit. Do not whine. Do not cry. You can't have that now. Listen to me. etc. Have her repeat what you say and then have her state what she should do instead of the negative behavior. This may need to take place after she has settled down. You need to regain your daughter's trust. Presently, she loves you but does not like you because of the baby.
The sticker/reward system will work. Give it about a month or so.
Hope this provides you with some insight. Have a great day!!!