It is ironic that when people want to be seen as tall, you want to reduce your height.
But reality is that you cannot reduce you height. On getting older slight hunch and bend comes and people tend to appear shorter.
If your problem is to match the height of your partner, or to appear as a bit shorter, then there are some suggestions which you may adopt. These will not make you shorter in height, but will make you appear shorter.
1. Wear dress with dark colour, and horizontal stripes.
2. If you are not overweight, try to put on a little more weight by taking more starchy food items and eating more. But a caution here, don't over do that. You may take advise of your doctor in this regard.
3. Wear only flat heeled footwear with very thin heels and base. But let the base material be strong to prevent tear by sharp objects and comfortable to feet.
4. Keep your hairdo as flat and sticking to the scalp.
5 While walking, avoid raising head and neck much, but keep a comfortable little bend or dip your head and face as if you are looking at your feet and road immediately in front of you.
6. Wear thick clothes and use thick inner dresses also that enhances your girth and body.
7.If walking with a partner who is less tall, keep a little distance so that others cannot easily notice the height difference. Let your partner do just the opposite of what is suggested to you form making partner look taller.( Vertical stripes. Light colour dress, thin dresses, high heeled footwear, raised hairdo etc)