Personally, I've found that the best way to go about it is to take it slow. Chams are solitary creatures for the most part, so creating a bond with them is not so simple and requires a lot of work.
Start by just sitting in the same room as her. If you have paperwork to do or homework, take a clipboard and pop yourself in a chair near her enclosure. Spend as much time in the same room as possible, and once she's comfortable with you being around her, move to feeding.
After some time and effort, she may warm up to you and feel comfortable enough to be handled. However, unfortunately, this isn't always the case and some chameleons prefer to just be left alone. But it can also go the other way, my current cham absolutely loves to be handled and will crawl up to my face and fall asleep on my nose.
Good luck!