Lemon- Just one lemon then diluted in a glass of water and taken with meal will bring good results.

Ginger- Make a teaspon of fresh ginger juice, and you can add honey to taste. This remedy is effective when taken once in the morning and once in the afternoon.

Honey- If a jug of honey is held under the nose of an asthmatic person and if he inhales the air that comes into contact with it, he starts breathing easier and deeper.

Other tips:
Steamy Bathroom
This is applicable to those who have hot and cold shower. When having an asthma, just go to bathroom and turn only the hot shower. Within in a minutes the bathroom will filled with steam. And the steam would help your breathing.

Fresh Air and Hot Coffee
Try hot and strong coffee. The caffeine will oven your lungs and airways. Don’t put milk or cream on it. Aside from Hot coffee, you can go somewhere where the air is cold and just sit and take a deep breaths.