If you really wanted to clean optics the cadillac way (which is usually overkill, but for the sake of argument...) you would want to use lens tissue and alcohol. For alcohol, methanol is good for dust, use acetone if there is really something gooey that you need to get off, but don't use acetone on plastic parts as it will eat it away. Methanol is good because it dries very clean, you're really just using it as an absorbant to soak up dust.
You fold up the lens tissue apply a few drops of alcohol and wipe the lens tissue across the surface ONCE. Then you must refold the tissue and repeat the procedure. The reason you only swipe once with each surface is so that if you collect any dust with the lens paper, you are not rubbing it across the lens element.
And if there is a soft element like a metal mirror, that you really need to clean, then basically, use the lens paper, don't fold it this time, but apply a few drops, lay it on the mirror, and just drag it off of the surface without applying any pressure. This will only get dust off, nothing sticky or gooey. I would not recommend doing this unless you think it is absolutely necessary.
This is probably overkill, but as I said, this is the obsessive compulsive way to clean optics.
Why do you say 50-50 alcohol and water Mitica? Out of curiosity...what is the benefit of the 50% water when cleaning optics?
EDIT* I just wanted to stress that this is a method for cleaning Optics. If you need to clean the camera body, I think distilled water and some sort of microfiber cloth would suffice. I would have recommended a mixture of ethanol and water for the body, but Mitica suggests not to, so I would look into that a little further before applying it to the plasticy components of the body. I certainly wouldn't use anything stronger than ethanol, such as methanol and especially not acetone.