winter jasmine care guide please
 

HI I have got a winter jasmine that i bought last yr and its looking a bit sorry for itself, when i bought it it had white flowers on and the leaves were a lovely dark shiny green.

its in a big pot in my front garden agaisnt a brick wall and its attached to a wrought iron climber for it to climb up. My front garden is south facing. The plant itself is about 6 ft tall as i bought it quite big! but has brown leaves on it the rest of the leaves dont look as green as when i bought it they are a very dull green and not a nice shiny healthy green- if you know what i mean. It is also a winter flowering jasmine and as yet has no flowers on it.

Can someone please give me some care guides on it. Thank you