1. I want to make my waist much slimmer. Is it possible - and how?

For many centuries, women (and men) were using corset for this purpose. Some women wanted to have the slimmest wais possible and were willing to do anything - even lace very tightly in a corset with a very small waist - and that meant even under 50 centimeters (or 20 inches) and less. You can find stories on internet claiming some women in history had 13" - 33 cm - waists; these are probably urban legends, but for it is possible to go to some 45 cm (17") without any harm.
But to have such waist you have to tightlace - that means wearing a corset all day (or preferably 24 hours - or sleep in a lighter night corset) and gradually lacing tighter and tighter. Once you get used to a 55 cm waist and are comfortable in the corset, go down another 2 centimeters, again wait, again lace down a little... Tightlacing is not easy, it is a lifestyle and you will have to do sacrifices.
An untrained woman can take off about 10 cm / 4 inches without much discomfort (or a little more, if she's plumper), a man a bit less because of the tighter muscles and stronger bones.
For more info on tightlacing search the web - you will find many websites and instructions for tightlacers.

2. I am a man and want to have a corset - will you make one for me?

Of course I will, many of my customers are men. You can have a male corset, not constructed to slim the waist, but to give support to the back and belly; or a female corset, if you want to feminize your figure. And you don't have to be shy, you won't be the first (nor the last) male owner of a Korzetty corset ;)

3. How should I care for my corset?

Don't wash your corset in water (and don't even think about the washing machine). You can have it dry cleaned (but remember dry cleaning can cause creasing) or clean it very carefully with a damp (not dripping wet) sponge or cloth. If you have a Desira boned corset without busk, water won't hurt the bones, so you can soak the corset (but don't forget the grommets - they can rust); but don't let water touch the busk, if you have a corset with busk; and be very, very careful with steel boned corset - the bones are coated, but even a little crack in the coating can make the bone rust. Don't wring the corset, let it dry lying on a clean towel. Corsets don't need ironing.
Every time you take your corset off, let it air out - hang it over a chair or hanger. Store the corset in a cool and dry place. Whenever you can, wear something under the corset - a tube top or a camisole that will absorb the perspiration. Sweat won't make your corset smell nice and it can even damage the fabric.
When lacing the corset, take your time and tighten the laces loop by loop. Never tug with the laces or try to lace too tight, especially for the first time - let the corset get used to your body and the body feel comfortable in the corset. Don't try to bend against the corset, you will break or damage the bones (steel bones and busks are more prone to breaking or remembering a wrong shape). Corsets are sturdy garments, but they are not immortal!

4. I have a plump figure, can I wear a corset?

Yes, corset are not for slim people only. Even a one meter (40") waist can look good in a corset.