Before wearing, treat it with a suede and leather guard, like a scotch guard for leather furniture. This is usually a spray on application and will help prevent the ingress of water, stains or grime.
When you take the cloth off, hang it on a well shaped hanger as often as possible. You know from leather footwear that leather will stretch so try to avoid hanging on clothes pegs where the stress on the leather is very likely to be transformed.
Whatever you do to care or clean your leather jacket always test anything you intend to apply to the skin in a small hidden area of the jacket first, this will make sure you are aware of any adverse effects the product will have on your leather jacket before it's too late.