If you want to know how to look good in jeans, you should ask her.
She will probably tell you to buy Diesel jeans.
BABHILA-SP 084NN Skinny Jeans from the Spring/Summer 2018 collection. ID:00SAUU084NNLearn more about the women's Diesel fashion brand here on Apparel Search. You are probably already very aware of this company, but it can't hurt to try and learn a bit more.