It’s hard to be funny, as the old adage goes: “Dying is easy. Comedy is hard.” Trying to make your writing funny is seriously unfunny. It’s like being held hostage at a dinner by the party bore.
I always followed the key advice given to budding stand-up comics; relax and have fun. If you’re having fun it will come through. If you are not having fun your readers will, like a stand-up’s audience, will give you a healthy response. With lots of fruit.

Quite true. Allowing humour to shine through in a scene is definitely a skill that requires cultivation if it doesn’t come naturally; I guess relaxing can be – ironically – hard to do at the best of times:)