There's a quote that states "How can you love someone else if you don't even love yourself?" that I personally disagree with. I can say that I do not love myself but I am capable of loving someone else. I'm not talking about loving my family because that comes naturally. I am not talking about loving chocolate or the summer. Those are things that I enjoy but loving someone is more than that. Loving someone is enjoying their presence and having to say goodbye to them is something you never want to do, even if it's just for a night. Here is how to love a girl who doesn't quite love herself yet.
Let her explore different things. If she wants to dye her hair purple one week and green the next, let her do her thing because most likely, it'll go back to brown after green. If she wants to pierce her nose, give her a fake nose ring and let her run with it. Most likely, she'll take it off after two days because she realized it's uncomfortable at night. If she wants to go to New York for a day, let her and even go with her. Seeing her look at everything could help you understand why she is the way she is. If you tell her no, she will fight you and do it anyways so tell her yes.
Don't shower her with compliments because you know she doesn't love herself yet. She knows you love her regardless of how she feels about herself. Instead of showing her your love, show her why she's lovable. Show her that she's hilarious and that when she talks about her favorite movie, her eyes light up and it is the most beautiful thing you have ever seen. Don't show her physical things because loving yourself is so much more then your exterior. Show her that she has the biggest heart of everyone you have ever met. Surround her with family and friends and show her that she is so loved and that you are all there for her.
Let her have her bad days. There will be days when there is a dark cloud over her head and no amount of sunshine can make it go away. Let her be and fight through it. It may even be a bad week or bad few days but she will get through it. Those are the times that seem to drag on forever but slowly, there will be less and less of them. There will be more sunshine and less rain and those days don't come for a while but they are so worth the wait.
Let her know she is capable. Make sure she knows that her love for you comes through. Show her that she is capable of loving you. Help her see that she is capable of so much, including loving herself. Lastly, don't push her too hard. When she is ready to love herself, she'll let you know.