I've had my Nikon D5100 for a week and I'm wondering what else I need to buy that is essential for starting out? I have 2 lenses (18-55mm and 55-300mm) and a camera bag. But that's it. A friend told me I need uv filters??? Is there anything else I should get? ..... And also is there a "correct" way to pack the camera bag? (as in lens standing face down/face up etc). I really want to look after my gear properly!